An attribute which indicates whether the patch is currently in
transition.
-What: /sys/kernel/livepatch/<patch>/signal
-Date: Nov 2017
-KernelVersion: 4.15.0
-Contact: live-patching@vger.kernel.org
-Description:
- A writable attribute that allows administrator to affect the
- course of an existing transition. Writing 1 sends a fake
- signal to all remaining blocking tasks. The fake signal
- means that no proper signal is delivered (there is no data in
- signal pending structures). Tasks are interrupted or woken up,
- and forced to change their patched state.
-
What: /sys/kernel/livepatch/<patch>/force
Date: Nov 2017
KernelVersion: 4.15.0
value may need to be updated accordingly.)
-Test cases
-==========
-
-What follows is not an exhaustive test suite of every possible livepatch
-pre/post-(un)patch combination, but a selection that demonstrates a few
-important concepts. Each test case uses the kernel modules located in
-the samples/livepatch/ and assumes that no livepatches are loaded at the
-beginning of the test.
-
-
-Test 1
-------
-
-Test a combination of loading a kernel module and a livepatch that
-patches a function in the first module. (Un)load the target module
-before the livepatch module:
-
-- load target module
-- load livepatch
-- disable livepatch
-- unload target module
-- unload livepatch
-
-First load a target module:
-
- % insmod samples/livepatch/livepatch-callbacks-mod.ko
- [ 34.475708] livepatch_callbacks_mod: livepatch_callbacks_mod_init
-
-On livepatch enable, before the livepatch transition starts, pre-patch
-callbacks are executed for vmlinux and livepatch_callbacks_mod (those
-klp_objects currently loaded). After klp_objects are patched according
-to the klp_patch, their post-patch callbacks run and the transition
-completes:
-
- % insmod samples/livepatch/livepatch-callbacks-demo.ko
- [ 36.503719] livepatch: enabling patch 'livepatch_callbacks_demo'
- [ 36.504213] livepatch: 'livepatch_callbacks_demo': initializing patching transition
- [ 36.504238] livepatch_callbacks_demo: pre_patch_callback: vmlinux
- [ 36.504721] livepatch_callbacks_demo: pre_patch_callback: livepatch_callbacks_mod -> [MODULE_STATE_LIVE] Normal state
- [ 36.505849] livepatch: 'livepatch_callbacks_demo': starting patching transition
- [ 37.727133] livepatch: 'livepatch_callbacks_demo': completing patching transition
- [ 37.727232] livepatch_callbacks_demo: post_patch_callback: vmlinux
- [ 37.727860] livepatch_callbacks_demo: post_patch_callback: livepatch_callbacks_mod -> [MODULE_STATE_LIVE] Normal state
- [ 37.728792] livepatch: 'livepatch_callbacks_demo': patching complete
-
-Similarly, on livepatch disable, pre-patch callbacks run before the
-unpatching transition starts. klp_objects are reverted, post-patch
-callbacks execute and the transition completes:
-
- % echo 0 > /sys/kernel/livepatch/livepatch_callbacks_demo/enabled
- [ 38.510209] livepatch: 'livepatch_callbacks_demo': initializing unpatching transition
- [ 38.510234] livepatch_callbacks_demo: pre_unpatch_callback: vmlinux
- [ 38.510982] livepatch_callbacks_demo: pre_unpatch_callback: livepatch_callbacks_mod -> [MODULE_STATE_LIVE] Normal state
- [ 38.512209] livepatch: 'livepatch_callbacks_demo': starting unpatching transition
- [ 39.711132] livepatch: 'livepatch_callbacks_demo': completing unpatching transition
- [ 39.711210] livepatch_callbacks_demo: post_unpatch_callback: vmlinux
- [ 39.711779] livepatch_callbacks_demo: post_unpatch_callback: livepatch_callbacks_mod -> [MODULE_STATE_LIVE] Normal state
- [ 39.712735] livepatch: 'livepatch_callbacks_demo': unpatching complete
-
- % rmmod samples/livepatch/livepatch-callbacks-demo.ko
- % rmmod samples/livepatch/livepatch-callbacks-mod.ko
- [ 42.534183] livepatch_callbacks_mod: livepatch_callbacks_mod_exit
-
-
-Test 2
-------
-
-This test is similar to the previous test, but (un)load the livepatch
-module before the target kernel module. This tests the livepatch core's
-module_coming handler:
-
-- load livepatch
-- load target module
-- disable livepatch
-- unload livepatch
-- unload target module
-
-
-On livepatch enable, only pre/post-patch callbacks are executed for
-currently loaded klp_objects, in this case, vmlinux:
-
- % insmod samples/livepatch/livepatch-callbacks-demo.ko
- [ 44.553328] livepatch: enabling patch 'livepatch_callbacks_demo'
- [ 44.553997] livepatch: 'livepatch_callbacks_demo': initializing patching transition
- [ 44.554049] livepatch_callbacks_demo: pre_patch_callback: vmlinux
- [ 44.554845] livepatch: 'livepatch_callbacks_demo': starting patching transition
- [ 45.727128] livepatch: 'livepatch_callbacks_demo': completing patching transition
- [ 45.727212] livepatch_callbacks_demo: post_patch_callback: vmlinux
- [ 45.727961] livepatch: 'livepatch_callbacks_demo': patching complete
-
-When a targeted module is subsequently loaded, only its pre/post-patch
-callbacks are executed:
-
- % insmod samples/livepatch/livepatch-callbacks-mod.ko
- [ 46.560845] livepatch: applying patch 'livepatch_callbacks_demo' to loading module 'livepatch_callbacks_mod'
- [ 46.561988] livepatch_callbacks_demo: pre_patch_callback: livepatch_callbacks_mod -> [MODULE_STATE_COMING] Full formed, running module_init
- [ 46.563452] livepatch_callbacks_demo: post_patch_callback: livepatch_callbacks_mod -> [MODULE_STATE_COMING] Full formed, running module_init
- [ 46.565495] livepatch_callbacks_mod: livepatch_callbacks_mod_init
-
-On livepatch disable, all currently loaded klp_objects' (vmlinux and
-livepatch_callbacks_mod) pre/post-unpatch callbacks are executed:
-
- % echo 0 > /sys/kernel/livepatch/livepatch_callbacks_demo/enabled
- [ 48.568885] livepatch: 'livepatch_callbacks_demo': initializing unpatching transition
- [ 48.568910] livepatch_callbacks_demo: pre_unpatch_callback: vmlinux
- [ 48.569441] livepatch_callbacks_demo: pre_unpatch_callback: livepatch_callbacks_mod -> [MODULE_STATE_LIVE] Normal state
- [ 48.570502] livepatch: 'livepatch_callbacks_demo': starting unpatching transition
- [ 49.759091] livepatch: 'livepatch_callbacks_demo': completing unpatching transition
- [ 49.759171] livepatch_callbacks_demo: post_unpatch_callback: vmlinux
- [ 49.759742] livepatch_callbacks_demo: post_unpatch_callback: livepatch_callbacks_mod -> [MODULE_STATE_LIVE] Normal state
- [ 49.760690] livepatch: 'livepatch_callbacks_demo': unpatching complete
-
- % rmmod samples/livepatch/livepatch-callbacks-demo.ko
- % rmmod samples/livepatch/livepatch-callbacks-mod.ko
- [ 52.592283] livepatch_callbacks_mod: livepatch_callbacks_mod_exit
-
-
-Test 3
-------
-
-Test loading the livepatch after a targeted kernel module, then unload
-the kernel module before disabling the livepatch. This tests the
-livepatch core's module_going handler:
-
-- load target module
-- load livepatch
-- unload target module
-- disable livepatch
-- unload livepatch
-
-First load a target module, then the livepatch:
-
- % insmod samples/livepatch/livepatch-callbacks-mod.ko
- [ 54.607948] livepatch_callbacks_mod: livepatch_callbacks_mod_init
-
- % insmod samples/livepatch/livepatch-callbacks-demo.ko
- [ 56.613919] livepatch: enabling patch 'livepatch_callbacks_demo'
- [ 56.614411] livepatch: 'livepatch_callbacks_demo': initializing patching transition
- [ 56.614436] livepatch_callbacks_demo: pre_patch_callback: vmlinux
- [ 56.614818] livepatch_callbacks_demo: pre_patch_callback: livepatch_callbacks_mod -> [MODULE_STATE_LIVE] Normal state
- [ 56.615656] livepatch: 'livepatch_callbacks_demo': starting patching transition
- [ 57.759070] livepatch: 'livepatch_callbacks_demo': completing patching transition
- [ 57.759147] livepatch_callbacks_demo: post_patch_callback: vmlinux
- [ 57.759621] livepatch_callbacks_demo: post_patch_callback: livepatch_callbacks_mod -> [MODULE_STATE_LIVE] Normal state
- [ 57.760307] livepatch: 'livepatch_callbacks_demo': patching complete
-
-When a target module is unloaded, the livepatch is only reverted from
-that klp_object (livepatch_callbacks_mod). As such, only its pre and
-post-unpatch callbacks are executed when this occurs:
-
- % rmmod samples/livepatch/livepatch-callbacks-mod.ko
- [ 58.623409] livepatch_callbacks_mod: livepatch_callbacks_mod_exit
- [ 58.623903] livepatch_callbacks_demo: pre_unpatch_callback: livepatch_callbacks_mod -> [MODULE_STATE_GOING] Going away
- [ 58.624658] livepatch: reverting patch 'livepatch_callbacks_demo' on unloading module 'livepatch_callbacks_mod'
- [ 58.625305] livepatch_callbacks_demo: post_unpatch_callback: livepatch_callbacks_mod -> [MODULE_STATE_GOING] Going away
-
-When the livepatch is disabled, pre and post-unpatch callbacks are run
-for the remaining klp_object, vmlinux:
-
- % echo 0 > /sys/kernel/livepatch/livepatch_callbacks_demo/enabled
- [ 60.638420] livepatch: 'livepatch_callbacks_demo': initializing unpatching transition
- [ 60.638444] livepatch_callbacks_demo: pre_unpatch_callback: vmlinux
- [ 60.638996] livepatch: 'livepatch_callbacks_demo': starting unpatching transition
- [ 61.727088] livepatch: 'livepatch_callbacks_demo': completing unpatching transition
- [ 61.727165] livepatch_callbacks_demo: post_unpatch_callback: vmlinux
- [ 61.727985] livepatch: 'livepatch_callbacks_demo': unpatching complete
-
- % rmmod samples/livepatch/livepatch-callbacks-demo.ko
-
-
-Test 4
-------
-
-This test is similar to the previous test, however the livepatch is
-loaded first. This tests the livepatch core's module_coming and
-module_going handlers:
-
-- load livepatch
-- load target module
-- unload target module
-- disable livepatch
-- unload livepatch
-
-First load the livepatch:
-
- % insmod samples/livepatch/livepatch-callbacks-demo.ko
- [ 64.661552] livepatch: enabling patch 'livepatch_callbacks_demo'
- [ 64.662147] livepatch: 'livepatch_callbacks_demo': initializing patching transition
- [ 64.662175] livepatch_callbacks_demo: pre_patch_callback: vmlinux
- [ 64.662850] livepatch: 'livepatch_callbacks_demo': starting patching transition
- [ 65.695056] livepatch: 'livepatch_callbacks_demo': completing patching transition
- [ 65.695147] livepatch_callbacks_demo: post_patch_callback: vmlinux
- [ 65.695561] livepatch: 'livepatch_callbacks_demo': patching complete
-
-When a targeted kernel module is subsequently loaded, only its
-pre/post-patch callbacks are executed:
-
- % insmod samples/livepatch/livepatch-callbacks-mod.ko
- [ 66.669196] livepatch: applying patch 'livepatch_callbacks_demo' to loading module 'livepatch_callbacks_mod'
- [ 66.669882] livepatch_callbacks_demo: pre_patch_callback: livepatch_callbacks_mod -> [MODULE_STATE_COMING] Full formed, running module_init
- [ 66.670744] livepatch_callbacks_demo: post_patch_callback: livepatch_callbacks_mod -> [MODULE_STATE_COMING] Full formed, running module_init
- [ 66.672873] livepatch_callbacks_mod: livepatch_callbacks_mod_init
-
-When the target module is unloaded, the livepatch is only reverted from
-the livepatch_callbacks_mod klp_object. As such, only pre and
-post-unpatch callbacks are executed when this occurs:
-
- % rmmod samples/livepatch/livepatch-callbacks-mod.ko
- [ 68.680065] livepatch_callbacks_mod: livepatch_callbacks_mod_exit
- [ 68.680688] livepatch_callbacks_demo: pre_unpatch_callback: livepatch_callbacks_mod -> [MODULE_STATE_GOING] Going away
- [ 68.681452] livepatch: reverting patch 'livepatch_callbacks_demo' on unloading module 'livepatch_callbacks_mod'
- [ 68.682094] livepatch_callbacks_demo: post_unpatch_callback: livepatch_callbacks_mod -> [MODULE_STATE_GOING] Going away
-
- % echo 0 > /sys/kernel/livepatch/livepatch_callbacks_demo/enabled
- [ 70.689225] livepatch: 'livepatch_callbacks_demo': initializing unpatching transition
- [ 70.689256] livepatch_callbacks_demo: pre_unpatch_callback: vmlinux
- [ 70.689882] livepatch: 'livepatch_callbacks_demo': starting unpatching transition
- [ 71.711080] livepatch: 'livepatch_callbacks_demo': completing unpatching transition
- [ 71.711481] livepatch_callbacks_demo: post_unpatch_callback: vmlinux
- [ 71.711988] livepatch: 'livepatch_callbacks_demo': unpatching complete
-
- % rmmod samples/livepatch/livepatch-callbacks-demo.ko
-
-
-Test 5
-------
-
-A simple test of loading a livepatch without one of its patch target
-klp_objects ever loaded (livepatch_callbacks_mod):
-
-- load livepatch
-- disable livepatch
-- unload livepatch
-
-Load the livepatch:
-
- % insmod samples/livepatch/livepatch-callbacks-demo.ko
- [ 74.711081] livepatch: enabling patch 'livepatch_callbacks_demo'
- [ 74.711595] livepatch: 'livepatch_callbacks_demo': initializing patching transition
- [ 74.711639] livepatch_callbacks_demo: pre_patch_callback: vmlinux
- [ 74.712272] livepatch: 'livepatch_callbacks_demo': starting patching transition
- [ 75.743137] livepatch: 'livepatch_callbacks_demo': completing patching transition
- [ 75.743219] livepatch_callbacks_demo: post_patch_callback: vmlinux
- [ 75.743867] livepatch: 'livepatch_callbacks_demo': patching complete
-
-As expected, only pre/post-(un)patch handlers are executed for vmlinux:
-
- % echo 0 > /sys/kernel/livepatch/livepatch_callbacks_demo/enabled
- [ 76.716254] livepatch: 'livepatch_callbacks_demo': initializing unpatching transition
- [ 76.716278] livepatch_callbacks_demo: pre_unpatch_callback: vmlinux
- [ 76.716666] livepatch: 'livepatch_callbacks_demo': starting unpatching transition
- [ 77.727089] livepatch: 'livepatch_callbacks_demo': completing unpatching transition
- [ 77.727194] livepatch_callbacks_demo: post_unpatch_callback: vmlinux
- [ 77.727907] livepatch: 'livepatch_callbacks_demo': unpatching complete
+Other Examples
+==============
- % rmmod samples/livepatch/livepatch-callbacks-demo.ko
-
-
-Test 6
-------
-
-Test a scenario where a vmlinux pre-patch callback returns a non-zero
-status (ie, failure):
-
-- load target module
-- load livepatch -ENODEV
-- unload target module
-
-First load a target module:
-
- % insmod samples/livepatch/livepatch-callbacks-mod.ko
- [ 80.740520] livepatch_callbacks_mod: livepatch_callbacks_mod_init
-
-Load the livepatch module, setting its 'pre_patch_ret' value to -19
-(-ENODEV). When its vmlinux pre-patch callback executed, this status
-code will propagate back to the module-loading subsystem. The result is
-that the insmod command refuses to load the livepatch module:
-
- % insmod samples/livepatch/livepatch-callbacks-demo.ko pre_patch_ret=-19
- [ 82.747326] livepatch: enabling patch 'livepatch_callbacks_demo'
- [ 82.747743] livepatch: 'livepatch_callbacks_demo': initializing patching transition
- [ 82.747767] livepatch_callbacks_demo: pre_patch_callback: vmlinux
- [ 82.748237] livepatch: pre-patch callback failed for object 'vmlinux'
- [ 82.748637] livepatch: failed to enable patch 'livepatch_callbacks_demo'
- [ 82.749059] livepatch: 'livepatch_callbacks_demo': canceling transition, going to unpatch
- [ 82.749060] livepatch: 'livepatch_callbacks_demo': completing unpatching transition
- [ 82.749868] livepatch: 'livepatch_callbacks_demo': unpatching complete
- [ 82.765809] insmod: ERROR: could not insert module samples/livepatch/livepatch-callbacks-demo.ko: No such device
-
- % rmmod samples/livepatch/livepatch-callbacks-mod.ko
- [ 84.774238] livepatch_callbacks_mod: livepatch_callbacks_mod_exit
-
-
-Test 7
-------
-
-Similar to the previous test, setup a livepatch such that its vmlinux
-pre-patch callback returns success. However, when a targeted kernel
-module is later loaded, have the livepatch return a failing status code:
-
-- load livepatch
-- setup -ENODEV
-- load target module
-- disable livepatch
-- unload livepatch
-
-Load the livepatch, notice vmlinux pre-patch callback succeeds:
-
- % insmod samples/livepatch/livepatch-callbacks-demo.ko
- [ 86.787845] livepatch: enabling patch 'livepatch_callbacks_demo'
- [ 86.788325] livepatch: 'livepatch_callbacks_demo': initializing patching transition
- [ 86.788427] livepatch_callbacks_demo: pre_patch_callback: vmlinux
- [ 86.788821] livepatch: 'livepatch_callbacks_demo': starting patching transition
- [ 87.711069] livepatch: 'livepatch_callbacks_demo': completing patching transition
- [ 87.711143] livepatch_callbacks_demo: post_patch_callback: vmlinux
- [ 87.711886] livepatch: 'livepatch_callbacks_demo': patching complete
-
-Set a trap so subsequent pre-patch callbacks to this livepatch will
-return -ENODEV:
-
- % echo -19 > /sys/module/livepatch_callbacks_demo/parameters/pre_patch_ret
-
-The livepatch pre-patch callback for subsequently loaded target modules
-will return failure, so the module loader refuses to load the kernel
-module. Notice that no post-patch or pre/post-unpatch callbacks are
-executed for this klp_object:
-
- % insmod samples/livepatch/livepatch-callbacks-mod.ko
- [ 90.796976] livepatch: applying patch 'livepatch_callbacks_demo' to loading module 'livepatch_callbacks_mod'
- [ 90.797834] livepatch_callbacks_demo: pre_patch_callback: livepatch_callbacks_mod -> [MODULE_STATE_COMING] Full formed, running module_init
- [ 90.798900] livepatch: pre-patch callback failed for object 'livepatch_callbacks_mod'
- [ 90.799652] livepatch: patch 'livepatch_callbacks_demo' failed for module 'livepatch_callbacks_mod', refusing to load module 'livepatch_callbacks_mod'
- [ 90.819737] insmod: ERROR: could not insert module samples/livepatch/livepatch-callbacks-mod.ko: No such device
-
-However, pre/post-unpatch callbacks run for the vmlinux klp_object:
-
- % echo 0 > /sys/kernel/livepatch/livepatch_callbacks_demo/enabled
- [ 92.823547] livepatch: 'livepatch_callbacks_demo': initializing unpatching transition
- [ 92.823573] livepatch_callbacks_demo: pre_unpatch_callback: vmlinux
- [ 92.824331] livepatch: 'livepatch_callbacks_demo': starting unpatching transition
- [ 93.727128] livepatch: 'livepatch_callbacks_demo': completing unpatching transition
- [ 93.727327] livepatch_callbacks_demo: post_unpatch_callback: vmlinux
- [ 93.727861] livepatch: 'livepatch_callbacks_demo': unpatching complete
-
- % rmmod samples/livepatch/livepatch-callbacks-demo.ko
-
-
-Test 8
-------
-
-Test loading multiple targeted kernel modules. This test-case is
-mainly for comparing with the next test-case.
-
-- load busy target module (0s sleep),
-- load livepatch
-- load target module
-- unload target module
-- disable livepatch
-- unload livepatch
-- unload busy target module
-
-
-Load a target "busy" kernel module which kicks off a worker function
-that immediately exits:
-
- % insmod samples/livepatch/livepatch-callbacks-busymod.ko sleep_secs=0
- [ 96.910107] livepatch_callbacks_busymod: livepatch_callbacks_mod_init
- [ 96.910600] livepatch_callbacks_busymod: busymod_work_func, sleeping 0 seconds ...
- [ 96.913024] livepatch_callbacks_busymod: busymod_work_func exit
-
-Proceed with loading the livepatch and another ordinary target module,
-notice that the post-patch callbacks are executed and the transition
-completes quickly:
-
- % insmod samples/livepatch/livepatch-callbacks-demo.ko
- [ 98.917892] livepatch: enabling patch 'livepatch_callbacks_demo'
- [ 98.918426] livepatch: 'livepatch_callbacks_demo': initializing patching transition
- [ 98.918453] livepatch_callbacks_demo: pre_patch_callback: vmlinux
- [ 98.918955] livepatch_callbacks_demo: pre_patch_callback: livepatch_callbacks_busymod -> [MODULE_STATE_LIVE] Normal state
- [ 98.923835] livepatch: 'livepatch_callbacks_demo': starting patching transition
- [ 99.743104] livepatch: 'livepatch_callbacks_demo': completing patching transition
- [ 99.743156] livepatch_callbacks_demo: post_patch_callback: vmlinux
- [ 99.743679] livepatch_callbacks_demo: post_patch_callback: livepatch_callbacks_busymod -> [MODULE_STATE_LIVE] Normal state
- [ 99.744616] livepatch: 'livepatch_callbacks_demo': patching complete
-
- % insmod samples/livepatch/livepatch-callbacks-mod.ko
- [ 100.930955] livepatch: applying patch 'livepatch_callbacks_demo' to loading module 'livepatch_callbacks_mod'
- [ 100.931668] livepatch_callbacks_demo: pre_patch_callback: livepatch_callbacks_mod -> [MODULE_STATE_COMING] Full formed, running module_init
- [ 100.932645] livepatch_callbacks_demo: post_patch_callback: livepatch_callbacks_mod -> [MODULE_STATE_COMING] Full formed, running module_init
- [ 100.934125] livepatch_callbacks_mod: livepatch_callbacks_mod_init
-
- % rmmod samples/livepatch/livepatch-callbacks-mod.ko
- [ 102.942805] livepatch_callbacks_mod: livepatch_callbacks_mod_exit
- [ 102.943640] livepatch_callbacks_demo: pre_unpatch_callback: livepatch_callbacks_mod -> [MODULE_STATE_GOING] Going away
- [ 102.944585] livepatch: reverting patch 'livepatch_callbacks_demo' on unloading module 'livepatch_callbacks_mod'
- [ 102.945455] livepatch_callbacks_demo: post_unpatch_callback: livepatch_callbacks_mod -> [MODULE_STATE_GOING] Going away
-
- % echo 0 > /sys/kernel/livepatch/livepatch_callbacks_demo/enabled
- [ 104.953815] livepatch: 'livepatch_callbacks_demo': initializing unpatching transition
- [ 104.953838] livepatch_callbacks_demo: pre_unpatch_callback: vmlinux
- [ 104.954431] livepatch_callbacks_demo: pre_unpatch_callback: livepatch_callbacks_busymod -> [MODULE_STATE_LIVE] Normal state
- [ 104.955426] livepatch: 'livepatch_callbacks_demo': starting unpatching transition
- [ 106.719073] livepatch: 'livepatch_callbacks_demo': completing unpatching transition
- [ 106.722633] livepatch_callbacks_demo: post_unpatch_callback: vmlinux
- [ 106.723282] livepatch_callbacks_demo: post_unpatch_callback: livepatch_callbacks_busymod -> [MODULE_STATE_LIVE] Normal state
- [ 106.724279] livepatch: 'livepatch_callbacks_demo': unpatching complete
-
- % rmmod samples/livepatch/livepatch-callbacks-demo.ko
- % rmmod samples/livepatch/livepatch-callbacks-busymod.ko
- [ 108.975660] livepatch_callbacks_busymod: livepatch_callbacks_mod_exit
-
-
-Test 9
-------
-
-A similar test as the previous one, but force the "busy" kernel module
-to do longer work.
-
-The livepatching core will refuse to patch a task that is currently
-executing a to-be-patched function -- the consistency model stalls the
-current patch transition until this safety-check is met. Test a
-scenario where one of a livepatch's target klp_objects sits on such a
-function for a long time. Meanwhile, load and unload other target
-kernel modules while the livepatch transition is in progress.
-
-- load busy target module (30s sleep)
-- load livepatch
-- load target module
-- unload target module
-- disable livepatch
-- unload livepatch
-- unload busy target module
-
-
-Load the "busy" kernel module, this time make it do 30 seconds worth of
-work:
-
- % insmod samples/livepatch/livepatch-callbacks-busymod.ko sleep_secs=30
- [ 110.993362] livepatch_callbacks_busymod: livepatch_callbacks_mod_init
- [ 110.994059] livepatch_callbacks_busymod: busymod_work_func, sleeping 30 seconds ...
-
-Meanwhile, the livepatch is loaded. Notice that the patch transition
-does not complete as the targeted "busy" module is sitting on a
-to-be-patched function:
-
- % insmod samples/livepatch/livepatch-callbacks-demo.ko
- [ 113.000309] livepatch: enabling patch 'livepatch_callbacks_demo'
- [ 113.000764] livepatch: 'livepatch_callbacks_demo': initializing patching transition
- [ 113.000791] livepatch_callbacks_demo: pre_patch_callback: vmlinux
- [ 113.001289] livepatch_callbacks_demo: pre_patch_callback: livepatch_callbacks_busymod -> [MODULE_STATE_LIVE] Normal state
- [ 113.005208] livepatch: 'livepatch_callbacks_demo': starting patching transition
-
-Load a second target module (this one is an ordinary idle kernel
-module). Note that *no* post-patch callbacks will be executed while the
-livepatch is still in transition:
-
- % insmod samples/livepatch/livepatch-callbacks-mod.ko
- [ 115.012740] livepatch: applying patch 'livepatch_callbacks_demo' to loading module 'livepatch_callbacks_mod'
- [ 115.013406] livepatch_callbacks_demo: pre_patch_callback: livepatch_callbacks_mod -> [MODULE_STATE_COMING] Full formed, running module_init
- [ 115.015315] livepatch_callbacks_mod: livepatch_callbacks_mod_init
-
-Request an unload of the simple kernel module. The patch is still
-transitioning, so its pre-unpatch callbacks are skipped:
-
- % rmmod samples/livepatch/livepatch-callbacks-mod.ko
- [ 117.022626] livepatch_callbacks_mod: livepatch_callbacks_mod_exit
- [ 117.023376] livepatch: reverting patch 'livepatch_callbacks_demo' on unloading module 'livepatch_callbacks_mod'
- [ 117.024533] livepatch_callbacks_demo: post_unpatch_callback: livepatch_callbacks_mod -> [MODULE_STATE_GOING] Going away
-
-Finally the livepatch is disabled. Since none of the patch's
-klp_object's post-patch callbacks executed, the remaining klp_object's
-pre-unpatch callbacks are skipped:
-
- % echo 0 > /sys/kernel/livepatch/livepatch_callbacks_demo/enabled
- [ 119.035408] livepatch: 'livepatch_callbacks_demo': reversing transition from patching to unpatching
- [ 119.035485] livepatch: 'livepatch_callbacks_demo': starting unpatching transition
- [ 119.711166] livepatch: 'livepatch_callbacks_demo': completing unpatching transition
- [ 119.714179] livepatch_callbacks_demo: post_unpatch_callback: vmlinux
- [ 119.714653] livepatch_callbacks_demo: post_unpatch_callback: livepatch_callbacks_busymod -> [MODULE_STATE_LIVE] Normal state
- [ 119.715437] livepatch: 'livepatch_callbacks_demo': unpatching complete
-
- % rmmod samples/livepatch/livepatch-callbacks-demo.ko
- % rmmod samples/livepatch/livepatch-callbacks-busymod.ko
- [ 141.279111] livepatch_callbacks_busymod: busymod_work_func exit
- [ 141.279760] livepatch_callbacks_busymod: livepatch_callbacks_mod_exit
+Sample livepatch modules demonstrating the callback API can be found in
+samples/livepatch/ directory. These samples were modified for use in
+kselftests and can be found in the lib/livepatch directory.
--- /dev/null
+===================================
+Atomic Replace & Cumulative Patches
+===================================
+
+There might be dependencies between livepatches. If multiple patches need
+to do different changes to the same function(s) then we need to define
+an order in which the patches will be installed. And function implementations
+from any newer livepatch must be done on top of the older ones.
+
+This might become a maintenance nightmare. Especially when more patches
+modified the same function in different ways.
+
+An elegant solution comes with the feature called "Atomic Replace". It allows
+creation of so called "Cumulative Patches". They include all wanted changes
+from all older livepatches and completely replace them in one transition.
+
+Usage
+-----
+
+The atomic replace can be enabled by setting "replace" flag in struct klp_patch,
+for example:
+
+ static struct klp_patch patch = {
+ .mod = THIS_MODULE,
+ .objs = objs,
+ .replace = true,
+ };
+
+All processes are then migrated to use the code only from the new patch.
+Once the transition is finished, all older patches are automatically
+disabled.
+
+Ftrace handlers are transparently removed from functions that are no
+longer modified by the new cumulative patch.
+
+As a result, the livepatch authors might maintain sources only for one
+cumulative patch. It helps to keep the patch consistent while adding or
+removing various fixes or features.
+
+Users could keep only the last patch installed on the system after
+the transition to has finished. It helps to clearly see what code is
+actually in use. Also the livepatch might then be seen as a "normal"
+module that modifies the kernel behavior. The only difference is that
+it can be updated at runtime without breaking its functionality.
+
+
+Features
+--------
+
+The atomic replace allows:
+
+ + Atomically revert some functions in a previous patch while
+ upgrading other functions.
+
+ + Remove eventual performance impact caused by core redirection
+ for functions that are no longer patched.
+
+ + Decrease user confusion about dependencies between livepatches.
+
+
+Limitations:
+------------
+
+ + Once the operation finishes, there is no straightforward way
+ to reverse it and restore the replaced patches atomically.
+
+ A good practice is to set .replace flag in any released livepatch.
+ Then re-adding an older livepatch is equivalent to downgrading
+ to that patch. This is safe as long as the livepatches do _not_ do
+ extra modifications in (un)patching callbacks or in the module_init()
+ or module_exit() functions, see below.
+
+ Also note that the replaced patch can be removed and loaded again
+ only when the transition was not forced.
+
+
+ + Only the (un)patching callbacks from the _new_ cumulative livepatch are
+ executed. Any callbacks from the replaced patches are ignored.
+
+ In other words, the cumulative patch is responsible for doing any actions
+ that are necessary to properly replace any older patch.
+
+ As a result, it might be dangerous to replace newer cumulative patches by
+ older ones. The old livepatches might not provide the necessary callbacks.
+
+ This might be seen as a limitation in some scenarios. But it makes life
+ easier in many others. Only the new cumulative livepatch knows what
+ fixes/features are added/removed and what special actions are necessary
+ for a smooth transition.
+
+ In any case, it would be a nightmare to think about the order of
+ the various callbacks and their interactions if the callbacks from all
+ enabled patches were called.
+
+
+ + There is no special handling of shadow variables. Livepatch authors
+ must create their own rules how to pass them from one cumulative
+ patch to the other. Especially that they should not blindly remove
+ them in module_exit() functions.
+
+ A good practice might be to remove shadow variables in the post-unpatch
+ callback. It is called only when the livepatch is properly disabled.
4. Livepatch module
4.1. New functions
4.2. Metadata
- 4.3. Livepatch module handling
5. Livepatch life-cycle
- 5.1. Registration
+ 5.1. Loading
5.2. Enabling
- 5.3. Disabling
- 5.4. Unregistration
+ 5.3. Replacing
+ 5.4. Disabling
+ 5.5. Removing
6. Sysfs
7. Limitations
the kernel livepatching.
The /sys/kernel/livepatch/<patch>/transition file shows whether a patch
-is in transition. Only a single patch (the topmost patch on the stack)
-can be in transition at a given time. A patch can remain in transition
-indefinitely, if any of the tasks are stuck in the initial patch state.
+is in transition. Only a single patch can be in transition at a given
+time. A patch can remain in transition indefinitely, if any of the tasks
+are stuck in the initial patch state.
A transition can be reversed and effectively canceled by writing the
opposite value to the /sys/kernel/livepatch/<patch>/enabled file while
unpatched and 1 to indicate it's patched. Otherwise, if no patch is in
transition, it shows -1. Any tasks which are blocking the transition
can be signaled with SIGSTOP and SIGCONT to force them to change their
-patched state. This may be harmful to the system though.
-/sys/kernel/livepatch/<patch>/signal attribute provides a better alternative.
-Writing 1 to the attribute sends a fake signal to all remaining blocking
-tasks. No proper signal is actually delivered (there is no data in signal
-pending structures). Tasks are interrupted or woken up, and forced to change
-their patched state.
+patched state. This may be harmful to the system though. Sending a fake signal
+to all remaining blocking tasks is a better alternative. No proper signal is
+actually delivered (there is no data in signal pending structures). Tasks are
+interrupted or woken up, and forced to change their patched state. The fake
+signal is automatically sent every 15 seconds.
Administrator can also affect a transition through
/sys/kernel/livepatch/<patch>/force attribute. Writing 1 there clears
see the "Consistency model" section.
-4.3. Livepatch module handling
-------------------------------
-
-The usual behavior is that the new functions will get used when
-the livepatch module is loaded. For this, the module init() function
-has to register the patch (struct klp_patch) and enable it. See the
-section "Livepatch life-cycle" below for more details about these
-two operations.
-
-Module removal is only safe when there are no users of the underlying
-functions. This is the reason why the force feature permanently disables
-the removal. The forced tasks entered the functions but we cannot say
-that they returned back. Therefore it cannot be decided when the
-livepatch module can be safely removed. When the system is successfully
-transitioned to a new patch state (patched/unpatched) without being
-forced it is guaranteed that no task sleeps or runs in the old code.
-
-
5. Livepatch life-cycle
=======================
-Livepatching defines four basic operations that define the life cycle of each
-live patch: registration, enabling, disabling and unregistration. There are
-several reasons why it is done this way.
+Livepatching can be described by five basic operations:
+loading, enabling, replacing, disabling, removing.
-First, the patch is applied only when all patched symbols for already
-loaded objects are found. The error handling is much easier if this
-check is done before particular functions get redirected.
+Where the replacing and the disabling operations are mutually
+exclusive. They have the same result for the given patch but
+not for the system.
-Second, it might take some time until the entire system is migrated with
-the hybrid consistency model being used. The patch revert might block
-the livepatch module removal for too long. Therefore it is useful to
-revert the patch using a separate operation that might be called
-explicitly. But it does not make sense to remove all information until
-the livepatch module is really removed.
+5.1. Loading
+------------
-5.1. Registration
------------------
+The only reasonable way is to enable the patch when the livepatch kernel
+module is being loaded. For this, klp_enable_patch() has to be called
+in the module_init() callback. There are two main reasons:
-Each patch first has to be registered using klp_register_patch(). This makes
-the patch known to the livepatch framework. Also it does some preliminary
-computing and checks.
+First, only the module has an easy access to the related struct klp_patch.
-In particular, the patch is added into the list of known patches. The
-addresses of the patched functions are found according to their names.
-The special relocations, mentioned in the section "New functions", are
-applied. The relevant entries are created under
-/sys/kernel/livepatch/<name>. The patch is rejected when any operation
-fails.
+Second, the error code might be used to refuse loading the module when
+the patch cannot get enabled.
5.2. Enabling
-------------
-Registered patches might be enabled either by calling klp_enable_patch() or
-by writing '1' to /sys/kernel/livepatch/<name>/enabled. The system will
-start using the new implementation of the patched functions at this stage.
+The livepatch gets enabled by calling klp_enable_patch() from
+the module_init() callback. The system will start using the new
+implementation of the patched functions at this stage.
-When a patch is enabled, livepatch enters into a transition state where
-tasks are converging to the patched state. This is indicated by a value
-of '1' in /sys/kernel/livepatch/<name>/transition. Once all tasks have
-been patched, the 'transition' value changes to '0'. For more
-information about this process, see the "Consistency model" section.
+First, the addresses of the patched functions are found according to their
+names. The special relocations, mentioned in the section "New functions",
+are applied. The relevant entries are created under
+/sys/kernel/livepatch/<name>. The patch is rejected when any above
+operation fails.
-If an original function is patched for the first time, a function
-specific struct klp_ops is created and an universal ftrace handler is
-registered.
+Second, livepatch enters into a transition state where tasks are converging
+to the patched state. If an original function is patched for the first
+time, a function specific struct klp_ops is created and an universal
+ftrace handler is registered[*]. This stage is indicated by a value of '1'
+in /sys/kernel/livepatch/<name>/transition. For more information about
+this process, see the "Consistency model" section.
-Functions might be patched multiple times. The ftrace handler is registered
-only once for the given function. Further patches just add an entry to the
-list (see field `func_stack`) of the struct klp_ops. The last added
-entry is chosen by the ftrace handler and becomes the active function
-replacement.
+Finally, once all tasks have been patched, the 'transition' value changes
+to '0'.
-Note that the patches might be enabled in a different order than they were
-registered.
+[*] Note that functions might be patched multiple times. The ftrace handler
+ is registered only once for a given function. Further patches just add
+ an entry to the list (see field `func_stack`) of the struct klp_ops.
+ The right implementation is selected by the ftrace handler, see
+ the "Consistency model" section.
+ That said, it is highly recommended to use cumulative livepatches
+ because they help keeping the consistency of all changes. In this case,
+ functions might be patched two times only during the transition period.
-5.3. Disabling
+
+5.3. Replacing
--------------
-Enabled patches might get disabled either by calling klp_disable_patch() or
-by writing '0' to /sys/kernel/livepatch/<name>/enabled. At this stage
-either the code from the previously enabled patch or even the original
-code gets used.
+All enabled patches might get replaced by a cumulative patch that
+has the .replace flag set.
+
+Once the new patch is enabled and the 'transition' finishes then
+all the functions (struct klp_func) associated with the replaced
+patches are removed from the corresponding struct klp_ops. Also
+the ftrace handler is unregistered and the struct klp_ops is
+freed when the related function is not modified by the new patch
+and func_stack list becomes empty.
+
+See Documentation/livepatch/cumulative-patches.txt for more details.
-When a patch is disabled, livepatch enters into a transition state where
-tasks are converging to the unpatched state. This is indicated by a
-value of '1' in /sys/kernel/livepatch/<name>/transition. Once all tasks
-have been unpatched, the 'transition' value changes to '0'. For more
-information about this process, see the "Consistency model" section.
-Here all the functions (struct klp_func) associated with the to-be-disabled
+5.4. Disabling
+--------------
+
+Enabled patches might get disabled by writing '0' to
+/sys/kernel/livepatch/<name>/enabled.
+
+First, livepatch enters into a transition state where tasks are converging
+to the unpatched state. The system starts using either the code from
+the previously enabled patch or even the original one. This stage is
+indicated by a value of '1' in /sys/kernel/livepatch/<name>/transition.
+For more information about this process, see the "Consistency model"
+section.
+
+Second, once all tasks have been unpatched, the 'transition' value changes
+to '0'. All the functions (struct klp_func) associated with the to-be-disabled
patch are removed from the corresponding struct klp_ops. The ftrace handler
is unregistered and the struct klp_ops is freed when the func_stack list
becomes empty.
-Patches must be disabled in exactly the reverse order in which they were
-enabled. It makes the problem and the implementation much easier.
-
+Third, the sysfs interface is destroyed.
-5.4. Unregistration
--------------------
-Disabled patches might be unregistered by calling klp_unregister_patch().
-This can be done only when the patch is disabled and the code is no longer
-used. It must be called before the livepatch module gets unloaded.
+5.5. Removing
+-------------
-At this stage, all the relevant sys-fs entries are removed and the patch
-is removed from the list of known patches.
+Module removal is only safe when there are no users of functions provided
+by the module. This is the reason why the force feature permanently
+disables the removal. Only when the system is successfully transitioned
+to a new patch state (patched/unpatched) without being forced it is
+guaranteed that no task sleeps or runs in the old code.
6. Sysfs
/sys/kernel/livepatch. The patches could be enabled and disabled
by writing there.
-/sys/kernel/livepatch/<patch>/signal and /sys/kernel/livepatch/<patch>/force
-attributes allow administrator to affect a patching operation.
+/sys/kernel/livepatch/<patch>/force attributes allow administrator to affect a
+patching operation.
See Documentation/ABI/testing/sysfs-kernel-livepatch for more details.
LIVE PATCHING
M: Josh Poimboeuf <jpoimboe@redhat.com>
-M: Jessica Yu <jeyu@kernel.org>
M: Jiri Kosina <jikos@kernel.org>
M: Miroslav Benes <mbenes@suse.cz>
-R: Petr Mladek <pmladek@suse.com>
+M: Petr Mladek <pmladek@suse.com>
+R: Joe Lawrence <joe.lawrence@redhat.com>
S: Maintained
F: kernel/livepatch/
F: include/linux/livepatch.h
F: Documentation/livepatch/
F: Documentation/ABI/testing/sysfs-kernel-livepatch
F: samples/livepatch/
+F: tools/testing/selftests/livepatch/
L: live-patching@vger.kernel.org
-T: git git://git.kernel.org/pub/scm/linux/kernel/git/jikos/livepatching.git
+T: git git://git.kernel.org/pub/scm/linux/kernel/git/livepatching/livepatching.git
LLC (802.2)
L: netdev@vger.kernel.org
#include <linux/module.h>
#include <linux/ftrace.h>
#include <linux/completion.h>
+#include <linux/list.h>
#if IS_ENABLED(CONFIG_LIVEPATCH)
* @new_func: pointer to the patched function code
* @old_sympos: a hint indicating which symbol position the old function
* can be found (optional)
- * @old_addr: the address of the function being patched
+ * @old_func: pointer to the function being patched
* @kobj: kobject for sysfs resources
+ * @node: list node for klp_object func_list
* @stack_node: list node for klp_ops func_stack list
* @old_size: size of the old function
* @new_size: size of the new function
+ * @kobj_added: @kobj has been added and needs freeing
+ * @nop: temporary patch to use the original code again; dyn. allocated
* @patched: the func has been added to the klp_ops list
* @transition: the func is currently being applied or reverted
*
unsigned long old_sympos;
/* internal */
- unsigned long old_addr;
+ void *old_func;
struct kobject kobj;
+ struct list_head node;
struct list_head stack_node;
unsigned long old_size, new_size;
+ bool kobj_added;
+ bool nop;
bool patched;
bool transition;
};
* @funcs: function entries for functions to be patched in the object
* @callbacks: functions to be executed pre/post (un)patching
* @kobj: kobject for sysfs resources
+ * @func_list: dynamic list of the function entries
+ * @node: list node for klp_patch obj_list
* @mod: kernel module associated with the patched object
* (NULL for vmlinux)
+ * @kobj_added: @kobj has been added and needs freeing
+ * @dynamic: temporary object for nop functions; dynamically allocated
* @patched: the object's funcs have been added to the klp_ops list
*/
struct klp_object {
/* internal */
struct kobject kobj;
+ struct list_head func_list;
+ struct list_head node;
struct module *mod;
+ bool kobj_added;
+ bool dynamic;
bool patched;
};
* struct klp_patch - patch structure for live patching
* @mod: reference to the live patch module
* @objs: object entries for kernel objects to be patched
- * @list: list node for global list of registered patches
+ * @replace: replace all actively used patches
+ * @list: list node for global list of actively used patches
* @kobj: kobject for sysfs resources
+ * @obj_list: dynamic list of the object entries
+ * @kobj_added: @kobj has been added and needs freeing
* @enabled: the patch is enabled (but operation may be incomplete)
+ * @forced: was involved in a forced transition
+ * @free_work: patch cleanup from workqueue-context
* @finish: for waiting till it is safe to remove the patch module
*/
struct klp_patch {
/* external */
struct module *mod;
struct klp_object *objs;
+ bool replace;
/* internal */
struct list_head list;
struct kobject kobj;
+ struct list_head obj_list;
+ bool kobj_added;
bool enabled;
+ bool forced;
+ struct work_struct free_work;
struct completion finish;
};
-#define klp_for_each_object(patch, obj) \
+#define klp_for_each_object_static(patch, obj) \
for (obj = patch->objs; obj->funcs || obj->name; obj++)
-#define klp_for_each_func(obj, func) \
+#define klp_for_each_object_safe(patch, obj, tmp_obj) \
+ list_for_each_entry_safe(obj, tmp_obj, &patch->obj_list, node)
+
+#define klp_for_each_object(patch, obj) \
+ list_for_each_entry(obj, &patch->obj_list, node)
+
+#define klp_for_each_func_static(obj, func) \
for (func = obj->funcs; \
func->old_name || func->new_func || func->old_sympos; \
func++)
-int klp_register_patch(struct klp_patch *);
-int klp_unregister_patch(struct klp_patch *);
+#define klp_for_each_func_safe(obj, func, tmp_func) \
+ list_for_each_entry_safe(func, tmp_func, &obj->func_list, node)
+
+#define klp_for_each_func(obj, func) \
+ list_for_each_entry(func, &obj->func_list, node)
+
int klp_enable_patch(struct klp_patch *);
-int klp_disable_patch(struct klp_patch *);
void arch_klp_init_object_loaded(struct klp_patch *patch,
struct klp_object *obj);
*/
DEFINE_MUTEX(klp_mutex);
-static LIST_HEAD(klp_patches);
+/*
+ * Actively used patches: enabled or in transition. Note that replaced
+ * or disabled patches are not listed even though the related kernel
+ * module still can be loaded.
+ */
+LIST_HEAD(klp_patches);
static struct kobject *klp_root_kobj;
mutex_unlock(&module_mutex);
}
-static bool klp_is_patch_registered(struct klp_patch *patch)
+static bool klp_initialized(void)
+{
+ return !!klp_root_kobj;
+}
+
+static struct klp_func *klp_find_func(struct klp_object *obj,
+ struct klp_func *old_func)
{
- struct klp_patch *mypatch;
+ struct klp_func *func;
- list_for_each_entry(mypatch, &klp_patches, list)
- if (mypatch == patch)
- return true;
+ klp_for_each_func(obj, func) {
+ if ((strcmp(old_func->old_name, func->old_name) == 0) &&
+ (old_func->old_sympos == func->old_sympos)) {
+ return func;
+ }
+ }
- return false;
+ return NULL;
}
-static bool klp_initialized(void)
+static struct klp_object *klp_find_object(struct klp_patch *patch,
+ struct klp_object *old_obj)
{
- return !!klp_root_kobj;
+ struct klp_object *obj;
+
+ klp_for_each_object(patch, obj) {
+ if (klp_is_module(old_obj)) {
+ if (klp_is_module(obj) &&
+ strcmp(old_obj->name, obj->name) == 0) {
+ return obj;
+ }
+ } else if (!klp_is_module(obj)) {
+ return obj;
+ }
+ }
+
+ return NULL;
}
struct klp_find_arg {
return ret;
}
-static int __klp_disable_patch(struct klp_patch *patch)
-{
- struct klp_object *obj;
-
- if (WARN_ON(!patch->enabled))
- return -EINVAL;
-
- if (klp_transition_patch)
- return -EBUSY;
-
- /* enforce stacking: only the last enabled patch can be disabled */
- if (!list_is_last(&patch->list, &klp_patches) &&
- list_next_entry(patch, list)->enabled)
- return -EBUSY;
-
- klp_init_transition(patch, KLP_UNPATCHED);
-
- klp_for_each_object(patch, obj)
- if (obj->patched)
- klp_pre_unpatch_callback(obj);
-
- /*
- * Enforce the order of the func->transition writes in
- * klp_init_transition() and the TIF_PATCH_PENDING writes in
- * klp_start_transition(). In the rare case where klp_ftrace_handler()
- * is called shortly after klp_update_patch_state() switches the task,
- * this ensures the handler sees that func->transition is set.
- */
- smp_wmb();
-
- klp_start_transition();
- klp_try_complete_transition();
- patch->enabled = false;
-
- return 0;
-}
-
-/**
- * klp_disable_patch() - disables a registered patch
- * @patch: The registered, enabled patch to be disabled
- *
- * Unregisters the patched functions from ftrace.
- *
- * Return: 0 on success, otherwise error
- */
-int klp_disable_patch(struct klp_patch *patch)
-{
- int ret;
-
- mutex_lock(&klp_mutex);
-
- if (!klp_is_patch_registered(patch)) {
- ret = -EINVAL;
- goto err;
- }
-
- if (!patch->enabled) {
- ret = -EINVAL;
- goto err;
- }
-
- ret = __klp_disable_patch(patch);
-
-err:
- mutex_unlock(&klp_mutex);
- return ret;
-}
-EXPORT_SYMBOL_GPL(klp_disable_patch);
-
-static int __klp_enable_patch(struct klp_patch *patch)
-{
- struct klp_object *obj;
- int ret;
-
- if (klp_transition_patch)
- return -EBUSY;
-
- if (WARN_ON(patch->enabled))
- return -EINVAL;
-
- /* enforce stacking: only the first disabled patch can be enabled */
- if (patch->list.prev != &klp_patches &&
- !list_prev_entry(patch, list)->enabled)
- return -EBUSY;
-
- /*
- * A reference is taken on the patch module to prevent it from being
- * unloaded.
- */
- if (!try_module_get(patch->mod))
- return -ENODEV;
-
- pr_notice("enabling patch '%s'\n", patch->mod->name);
-
- klp_init_transition(patch, KLP_PATCHED);
-
- /*
- * Enforce the order of the func->transition writes in
- * klp_init_transition() and the ops->func_stack writes in
- * klp_patch_object(), so that klp_ftrace_handler() will see the
- * func->transition updates before the handler is registered and the
- * new funcs become visible to the handler.
- */
- smp_wmb();
-
- klp_for_each_object(patch, obj) {
- if (!klp_is_object_loaded(obj))
- continue;
-
- ret = klp_pre_patch_callback(obj);
- if (ret) {
- pr_warn("pre-patch callback failed for object '%s'\n",
- klp_is_module(obj) ? obj->name : "vmlinux");
- goto err;
- }
-
- ret = klp_patch_object(obj);
- if (ret) {
- pr_warn("failed to patch object '%s'\n",
- klp_is_module(obj) ? obj->name : "vmlinux");
- goto err;
- }
- }
-
- klp_start_transition();
- klp_try_complete_transition();
- patch->enabled = true;
-
- return 0;
-err:
- pr_warn("failed to enable patch '%s'\n", patch->mod->name);
-
- klp_cancel_transition();
- return ret;
-}
-
-/**
- * klp_enable_patch() - enables a registered patch
- * @patch: The registered, disabled patch to be enabled
- *
- * Performs the needed symbol lookups and code relocations,
- * then registers the patched functions with ftrace.
- *
- * Return: 0 on success, otherwise error
- */
-int klp_enable_patch(struct klp_patch *patch)
-{
- int ret;
-
- mutex_lock(&klp_mutex);
-
- if (!klp_is_patch_registered(patch)) {
- ret = -EINVAL;
- goto err;
- }
-
- ret = __klp_enable_patch(patch);
-
-err:
- mutex_unlock(&klp_mutex);
- return ret;
-}
-EXPORT_SYMBOL_GPL(klp_enable_patch);
-
/*
* Sysfs Interface
*
* /sys/kernel/livepatch/<patch>
* /sys/kernel/livepatch/<patch>/enabled
* /sys/kernel/livepatch/<patch>/transition
- * /sys/kernel/livepatch/<patch>/signal
* /sys/kernel/livepatch/<patch>/force
* /sys/kernel/livepatch/<patch>/<object>
* /sys/kernel/livepatch/<patch>/<object>/<function,sympos>
*/
+static int __klp_disable_patch(struct klp_patch *patch);
static ssize_t enabled_store(struct kobject *kobj, struct kobj_attribute *attr,
const char *buf, size_t count)
mutex_lock(&klp_mutex);
- if (!klp_is_patch_registered(patch)) {
- /*
- * Module with the patch could either disappear meanwhile or is
- * not properly initialized yet.
- */
- ret = -EINVAL;
- goto err;
- }
-
if (patch->enabled == enabled) {
/* already in requested state */
ret = -EINVAL;
- goto err;
+ goto out;
}
- if (patch == klp_transition_patch) {
+ /*
+ * Allow to reverse a pending transition in both ways. It might be
+ * necessary to complete the transition without forcing and breaking
+ * the system integrity.
+ *
+ * Do not allow to re-enable a disabled patch.
+ */
+ if (patch == klp_transition_patch)
klp_reverse_transition();
- } else if (enabled) {
- ret = __klp_enable_patch(patch);
- if (ret)
- goto err;
- } else {
+ else if (!enabled)
ret = __klp_disable_patch(patch);
- if (ret)
- goto err;
- }
+ else
+ ret = -EINVAL;
+out:
mutex_unlock(&klp_mutex);
+ if (ret)
+ return ret;
return count;
-
-err:
- mutex_unlock(&klp_mutex);
- return ret;
}
static ssize_t enabled_show(struct kobject *kobj,
patch == klp_transition_patch);
}
-static ssize_t signal_store(struct kobject *kobj, struct kobj_attribute *attr,
- const char *buf, size_t count)
-{
- struct klp_patch *patch;
- int ret;
- bool val;
-
- ret = kstrtobool(buf, &val);
- if (ret)
- return ret;
-
- if (!val)
- return count;
-
- mutex_lock(&klp_mutex);
-
- patch = container_of(kobj, struct klp_patch, kobj);
- if (patch != klp_transition_patch) {
- mutex_unlock(&klp_mutex);
- return -EINVAL;
- }
-
- klp_send_signals();
-
- mutex_unlock(&klp_mutex);
-
- return count;
-}
-
static ssize_t force_store(struct kobject *kobj, struct kobj_attribute *attr,
const char *buf, size_t count)
{
static struct kobj_attribute enabled_kobj_attr = __ATTR_RW(enabled);
static struct kobj_attribute transition_kobj_attr = __ATTR_RO(transition);
-static struct kobj_attribute signal_kobj_attr = __ATTR_WO(signal);
static struct kobj_attribute force_kobj_attr = __ATTR_WO(force);
static struct attribute *klp_patch_attrs[] = {
&enabled_kobj_attr.attr,
&transition_kobj_attr.attr,
- &signal_kobj_attr.attr,
&force_kobj_attr.attr,
NULL
};
+static void klp_free_object_dynamic(struct klp_object *obj)
+{
+ kfree(obj->name);
+ kfree(obj);
+}
+
+static struct klp_object *klp_alloc_object_dynamic(const char *name)
+{
+ struct klp_object *obj;
+
+ obj = kzalloc(sizeof(*obj), GFP_KERNEL);
+ if (!obj)
+ return NULL;
+
+ if (name) {
+ obj->name = kstrdup(name, GFP_KERNEL);
+ if (!obj->name) {
+ kfree(obj);
+ return NULL;
+ }
+ }
+
+ INIT_LIST_HEAD(&obj->func_list);
+ obj->dynamic = true;
+
+ return obj;
+}
+
+static void klp_free_func_nop(struct klp_func *func)
+{
+ kfree(func->old_name);
+ kfree(func);
+}
+
+static struct klp_func *klp_alloc_func_nop(struct klp_func *old_func,
+ struct klp_object *obj)
+{
+ struct klp_func *func;
+
+ func = kzalloc(sizeof(*func), GFP_KERNEL);
+ if (!func)
+ return NULL;
+
+ if (old_func->old_name) {
+ func->old_name = kstrdup(old_func->old_name, GFP_KERNEL);
+ if (!func->old_name) {
+ kfree(func);
+ return NULL;
+ }
+ }
+
+ /*
+ * func->new_func is same as func->old_func. These addresses are
+ * set when the object is loaded, see klp_init_object_loaded().
+ */
+ func->old_sympos = old_func->old_sympos;
+ func->nop = true;
+
+ return func;
+}
+
+static int klp_add_object_nops(struct klp_patch *patch,
+ struct klp_object *old_obj)
+{
+ struct klp_object *obj;
+ struct klp_func *func, *old_func;
+
+ obj = klp_find_object(patch, old_obj);
+
+ if (!obj) {
+ obj = klp_alloc_object_dynamic(old_obj->name);
+ if (!obj)
+ return -ENOMEM;
+
+ list_add_tail(&obj->node, &patch->obj_list);
+ }
+
+ klp_for_each_func(old_obj, old_func) {
+ func = klp_find_func(obj, old_func);
+ if (func)
+ continue;
+
+ func = klp_alloc_func_nop(old_func, obj);
+ if (!func)
+ return -ENOMEM;
+
+ list_add_tail(&func->node, &obj->func_list);
+ }
+
+ return 0;
+}
+
+/*
+ * Add 'nop' functions which simply return to the caller to run
+ * the original function. The 'nop' functions are added to a
+ * patch to facilitate a 'replace' mode.
+ */
+static int klp_add_nops(struct klp_patch *patch)
+{
+ struct klp_patch *old_patch;
+ struct klp_object *old_obj;
+
+ klp_for_each_patch(old_patch) {
+ klp_for_each_object(old_patch, old_obj) {
+ int err;
+
+ err = klp_add_object_nops(patch, old_obj);
+ if (err)
+ return err;
+ }
+ }
+
+ return 0;
+}
+
static void klp_kobj_release_patch(struct kobject *kobj)
{
struct klp_patch *patch;
static void klp_kobj_release_object(struct kobject *kobj)
{
+ struct klp_object *obj;
+
+ obj = container_of(kobj, struct klp_object, kobj);
+
+ if (obj->dynamic)
+ klp_free_object_dynamic(obj);
}
static struct kobj_type klp_ktype_object = {
static void klp_kobj_release_func(struct kobject *kobj)
{
+ struct klp_func *func;
+
+ func = container_of(kobj, struct klp_func, kobj);
+
+ if (func->nop)
+ klp_free_func_nop(func);
}
static struct kobj_type klp_ktype_func = {
.sysfs_ops = &kobj_sysfs_ops,
};
-/*
- * Free all functions' kobjects in the array up to some limit. When limit is
- * NULL, all kobjects are freed.
- */
-static void klp_free_funcs_limited(struct klp_object *obj,
- struct klp_func *limit)
+static void __klp_free_funcs(struct klp_object *obj, bool nops_only)
{
- struct klp_func *func;
+ struct klp_func *func, *tmp_func;
+
+ klp_for_each_func_safe(obj, func, tmp_func) {
+ if (nops_only && !func->nop)
+ continue;
+
+ list_del(&func->node);
- for (func = obj->funcs; func->old_name && func != limit; func++)
- kobject_put(&func->kobj);
+ /* Might be called from klp_init_patch() error path. */
+ if (func->kobj_added) {
+ kobject_put(&func->kobj);
+ } else if (func->nop) {
+ klp_free_func_nop(func);
+ }
+ }
}
/* Clean up when a patched object is unloaded */
obj->mod = NULL;
- klp_for_each_func(obj, func)
- func->old_addr = 0;
+ klp_for_each_func(obj, func) {
+ func->old_func = NULL;
+
+ if (func->nop)
+ func->new_func = NULL;
+ }
}
-/*
- * Free all objects' kobjects in the array up to some limit. When limit is
- * NULL, all kobjects are freed.
- */
-static void klp_free_objects_limited(struct klp_patch *patch,
- struct klp_object *limit)
+static void __klp_free_objects(struct klp_patch *patch, bool nops_only)
{
- struct klp_object *obj;
+ struct klp_object *obj, *tmp_obj;
+
+ klp_for_each_object_safe(patch, obj, tmp_obj) {
+ __klp_free_funcs(obj, nops_only);
+
+ if (nops_only && !obj->dynamic)
+ continue;
+
+ list_del(&obj->node);
- for (obj = patch->objs; obj->funcs && obj != limit; obj++) {
- klp_free_funcs_limited(obj, NULL);
- kobject_put(&obj->kobj);
+ /* Might be called from klp_init_patch() error path. */
+ if (obj->kobj_added) {
+ kobject_put(&obj->kobj);
+ } else if (obj->dynamic) {
+ klp_free_object_dynamic(obj);
+ }
}
}
-static void klp_free_patch(struct klp_patch *patch)
+static void klp_free_objects(struct klp_patch *patch)
+{
+ __klp_free_objects(patch, false);
+}
+
+static void klp_free_objects_dynamic(struct klp_patch *patch)
+{
+ __klp_free_objects(patch, true);
+}
+
+/*
+ * This function implements the free operations that can be called safely
+ * under klp_mutex.
+ *
+ * The operation must be completed by calling klp_free_patch_finish()
+ * outside klp_mutex.
+ */
+void klp_free_patch_start(struct klp_patch *patch)
{
- klp_free_objects_limited(patch, NULL);
if (!list_empty(&patch->list))
list_del(&patch->list);
+
+ klp_free_objects(patch);
+}
+
+/*
+ * This function implements the free part that must be called outside
+ * klp_mutex.
+ *
+ * It must be called after klp_free_patch_start(). And it has to be
+ * the last function accessing the livepatch structures when the patch
+ * gets disabled.
+ */
+static void klp_free_patch_finish(struct klp_patch *patch)
+{
+ /*
+ * Avoid deadlock with enabled_store() sysfs callback by
+ * calling this outside klp_mutex. It is safe because
+ * this is called when the patch gets disabled and it
+ * cannot get enabled again.
+ */
+ if (patch->kobj_added) {
+ kobject_put(&patch->kobj);
+ wait_for_completion(&patch->finish);
+ }
+
+ /* Put the module after the last access to struct klp_patch. */
+ if (!patch->forced)
+ module_put(patch->mod);
+}
+
+/*
+ * The livepatch might be freed from sysfs interface created by the patch.
+ * This work allows to wait until the interface is destroyed in a separate
+ * context.
+ */
+static void klp_free_patch_work_fn(struct work_struct *work)
+{
+ struct klp_patch *patch =
+ container_of(work, struct klp_patch, free_work);
+
+ klp_free_patch_finish(patch);
}
static int klp_init_func(struct klp_object *obj, struct klp_func *func)
{
- if (!func->old_name || !func->new_func)
+ int ret;
+
+ if (!func->old_name)
+ return -EINVAL;
+
+ /*
+ * NOPs get the address later. The patched module must be loaded,
+ * see klp_init_object_loaded().
+ */
+ if (!func->new_func && !func->nop)
return -EINVAL;
if (strlen(func->old_name) >= KSYM_NAME_LEN)
* object. If the user selects 0 for old_sympos, then 1 will be used
* since a unique symbol will be the first occurrence.
*/
- return kobject_init_and_add(&func->kobj, &klp_ktype_func,
- &obj->kobj, "%s,%lu", func->old_name,
- func->old_sympos ? func->old_sympos : 1);
+ ret = kobject_init_and_add(&func->kobj, &klp_ktype_func,
+ &obj->kobj, "%s,%lu", func->old_name,
+ func->old_sympos ? func->old_sympos : 1);
+ if (!ret)
+ func->kobj_added = true;
+
+ return ret;
}
/* Arches may override this to finish any remaining arch-specific tasks */
klp_for_each_func(obj, func) {
ret = klp_find_object_symbol(obj->name, func->old_name,
func->old_sympos,
- &func->old_addr);
+ (unsigned long *)&func->old_func);
if (ret)
return ret;
- ret = kallsyms_lookup_size_offset(func->old_addr,
+ ret = kallsyms_lookup_size_offset((unsigned long)func->old_func,
&func->old_size, NULL);
if (!ret) {
pr_err("kallsyms size lookup failed for '%s'\n",
return -ENOENT;
}
+ if (func->nop)
+ func->new_func = func->old_func;
+
ret = kallsyms_lookup_size_offset((unsigned long)func->new_func,
&func->new_size, NULL);
if (!ret) {
int ret;
const char *name;
- if (!obj->funcs)
- return -EINVAL;
-
if (klp_is_module(obj) && strlen(obj->name) >= MODULE_NAME_LEN)
return -EINVAL;
&patch->kobj, "%s", name);
if (ret)
return ret;
+ obj->kobj_added = true;
klp_for_each_func(obj, func) {
ret = klp_init_func(obj, func);
if (ret)
- goto free;
+ return ret;
}
- if (klp_is_object_loaded(obj)) {
+ if (klp_is_object_loaded(obj))
ret = klp_init_object_loaded(patch, obj);
- if (ret)
- goto free;
- }
- return 0;
-
-free:
- klp_free_funcs_limited(obj, func);
- kobject_put(&obj->kobj);
return ret;
}
-static int klp_init_patch(struct klp_patch *patch)
+static int klp_init_patch_early(struct klp_patch *patch)
{
struct klp_object *obj;
- int ret;
+ struct klp_func *func;
if (!patch->objs)
return -EINVAL;
- mutex_lock(&klp_mutex);
-
+ INIT_LIST_HEAD(&patch->list);
+ INIT_LIST_HEAD(&patch->obj_list);
+ patch->kobj_added = false;
patch->enabled = false;
+ patch->forced = false;
+ INIT_WORK(&patch->free_work, klp_free_patch_work_fn);
init_completion(&patch->finish);
+ klp_for_each_object_static(patch, obj) {
+ if (!obj->funcs)
+ return -EINVAL;
+
+ INIT_LIST_HEAD(&obj->func_list);
+ obj->kobj_added = false;
+ list_add_tail(&obj->node, &patch->obj_list);
+
+ klp_for_each_func_static(obj, func) {
+ func->kobj_added = false;
+ list_add_tail(&func->node, &obj->func_list);
+ }
+ }
+
+ if (!try_module_get(patch->mod))
+ return -ENODEV;
+
+ return 0;
+}
+
+static int klp_init_patch(struct klp_patch *patch)
+{
+ struct klp_object *obj;
+ int ret;
+
ret = kobject_init_and_add(&patch->kobj, &klp_ktype_patch,
klp_root_kobj, "%s", patch->mod->name);
- if (ret) {
- mutex_unlock(&klp_mutex);
+ if (ret)
return ret;
+ patch->kobj_added = true;
+
+ if (patch->replace) {
+ ret = klp_add_nops(patch);
+ if (ret)
+ return ret;
}
klp_for_each_object(patch, obj) {
ret = klp_init_object(patch, obj);
if (ret)
- goto free;
+ return ret;
}
list_add_tail(&patch->list, &klp_patches);
- mutex_unlock(&klp_mutex);
-
return 0;
+}
-free:
- klp_free_objects_limited(patch, obj);
+static int __klp_disable_patch(struct klp_patch *patch)
+{
+ struct klp_object *obj;
- mutex_unlock(&klp_mutex);
+ if (WARN_ON(!patch->enabled))
+ return -EINVAL;
- kobject_put(&patch->kobj);
- wait_for_completion(&patch->finish);
+ if (klp_transition_patch)
+ return -EBUSY;
- return ret;
+ klp_init_transition(patch, KLP_UNPATCHED);
+
+ klp_for_each_object(patch, obj)
+ if (obj->patched)
+ klp_pre_unpatch_callback(obj);
+
+ /*
+ * Enforce the order of the func->transition writes in
+ * klp_init_transition() and the TIF_PATCH_PENDING writes in
+ * klp_start_transition(). In the rare case where klp_ftrace_handler()
+ * is called shortly after klp_update_patch_state() switches the task,
+ * this ensures the handler sees that func->transition is set.
+ */
+ smp_wmb();
+
+ klp_start_transition();
+ patch->enabled = false;
+ klp_try_complete_transition();
+
+ return 0;
}
-/**
- * klp_unregister_patch() - unregisters a patch
- * @patch: Disabled patch to be unregistered
- *
- * Frees the data structures and removes the sysfs interface.
- *
- * Return: 0 on success, otherwise error
- */
-int klp_unregister_patch(struct klp_patch *patch)
+static int __klp_enable_patch(struct klp_patch *patch)
{
+ struct klp_object *obj;
int ret;
- mutex_lock(&klp_mutex);
+ if (klp_transition_patch)
+ return -EBUSY;
- if (!klp_is_patch_registered(patch)) {
- ret = -EINVAL;
- goto err;
- }
+ if (WARN_ON(patch->enabled))
+ return -EINVAL;
- if (patch->enabled) {
- ret = -EBUSY;
- goto err;
- }
+ if (!patch->kobj_added)
+ return -EINVAL;
- klp_free_patch(patch);
+ pr_notice("enabling patch '%s'\n", patch->mod->name);
- mutex_unlock(&klp_mutex);
+ klp_init_transition(patch, KLP_PATCHED);
+
+ /*
+ * Enforce the order of the func->transition writes in
+ * klp_init_transition() and the ops->func_stack writes in
+ * klp_patch_object(), so that klp_ftrace_handler() will see the
+ * func->transition updates before the handler is registered and the
+ * new funcs become visible to the handler.
+ */
+ smp_wmb();
+
+ klp_for_each_object(patch, obj) {
+ if (!klp_is_object_loaded(obj))
+ continue;
+
+ ret = klp_pre_patch_callback(obj);
+ if (ret) {
+ pr_warn("pre-patch callback failed for object '%s'\n",
+ klp_is_module(obj) ? obj->name : "vmlinux");
+ goto err;
+ }
+
+ ret = klp_patch_object(obj);
+ if (ret) {
+ pr_warn("failed to patch object '%s'\n",
+ klp_is_module(obj) ? obj->name : "vmlinux");
+ goto err;
+ }
+ }
- kobject_put(&patch->kobj);
- wait_for_completion(&patch->finish);
+ klp_start_transition();
+ patch->enabled = true;
+ klp_try_complete_transition();
return 0;
err:
- mutex_unlock(&klp_mutex);
+ pr_warn("failed to enable patch '%s'\n", patch->mod->name);
+
+ klp_cancel_transition();
return ret;
}
-EXPORT_SYMBOL_GPL(klp_unregister_patch);
/**
- * klp_register_patch() - registers a patch
- * @patch: Patch to be registered
+ * klp_enable_patch() - enable the livepatch
+ * @patch: patch to be enabled
*
- * Initializes the data structure associated with the patch and
- * creates the sysfs interface.
+ * Initializes the data structure associated with the patch, creates the sysfs
+ * interface, performs the needed symbol lookups and code relocations,
+ * registers the patched functions with ftrace.
*
- * There is no need to take the reference on the patch module here. It is done
- * later when the patch is enabled.
+ * This function is supposed to be called from the livepatch module_init()
+ * callback.
*
* Return: 0 on success, otherwise error
*/
-int klp_register_patch(struct klp_patch *patch)
+int klp_enable_patch(struct klp_patch *patch)
{
+ int ret;
+
if (!patch || !patch->mod)
return -EINVAL;
if (!klp_have_reliable_stack()) {
pr_err("This architecture doesn't have support for the livepatch consistency model.\n");
- return -ENOSYS;
+ return -EOPNOTSUPP;
+ }
+
+
+ mutex_lock(&klp_mutex);
+
+ ret = klp_init_patch_early(patch);
+ if (ret) {
+ mutex_unlock(&klp_mutex);
+ return ret;
}
- return klp_init_patch(patch);
+ ret = klp_init_patch(patch);
+ if (ret)
+ goto err;
+
+ ret = __klp_enable_patch(patch);
+ if (ret)
+ goto err;
+
+ mutex_unlock(&klp_mutex);
+
+ return 0;
+
+err:
+ klp_free_patch_start(patch);
+
+ mutex_unlock(&klp_mutex);
+
+ klp_free_patch_finish(patch);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(klp_enable_patch);
+
+/*
+ * This function removes replaced patches.
+ *
+ * We could be pretty aggressive here. It is called in the situation where
+ * these structures are no longer accessible. All functions are redirected
+ * by the klp_transition_patch. They use either a new code or they are in
+ * the original code because of the special nop function patches.
+ *
+ * The only exception is when the transition was forced. In this case,
+ * klp_ftrace_handler() might still see the replaced patch on the stack.
+ * Fortunately, it is carefully designed to work with removed functions
+ * thanks to RCU. We only have to keep the patches on the system. Also
+ * this is handled transparently by patch->module_put.
+ */
+void klp_discard_replaced_patches(struct klp_patch *new_patch)
+{
+ struct klp_patch *old_patch, *tmp_patch;
+
+ klp_for_each_patch_safe(old_patch, tmp_patch) {
+ if (old_patch == new_patch)
+ return;
+
+ old_patch->enabled = false;
+ klp_unpatch_objects(old_patch);
+ klp_free_patch_start(old_patch);
+ schedule_work(&old_patch->free_work);
+ }
+}
+
+/*
+ * This function removes the dynamically allocated 'nop' functions.
+ *
+ * We could be pretty aggressive. NOPs do not change the existing
+ * behavior except for adding unnecessary delay by the ftrace handler.
+ *
+ * It is safe even when the transition was forced. The ftrace handler
+ * will see a valid ops->func_stack entry thanks to RCU.
+ *
+ * We could even free the NOPs structures. They must be the last entry
+ * in ops->func_stack. Therefore unregister_ftrace_function() is called.
+ * It does the same as klp_synchronize_transition() to make sure that
+ * nobody is inside the ftrace handler once the operation finishes.
+ *
+ * IMPORTANT: It must be called right after removing the replaced patches!
+ */
+void klp_discard_nops(struct klp_patch *new_patch)
+{
+ klp_unpatch_objects_dynamic(klp_transition_patch);
+ klp_free_objects_dynamic(klp_transition_patch);
}
-EXPORT_SYMBOL_GPL(klp_register_patch);
/*
* Remove parts of patches that touch a given kernel module. The list of
struct klp_patch *patch;
struct klp_object *obj;
- list_for_each_entry(patch, &klp_patches, list) {
+ klp_for_each_patch(patch) {
if (patch == limit)
break;
if (!klp_is_module(obj) || strcmp(obj->name, mod->name))
continue;
- /*
- * Only unpatch the module if the patch is enabled or
- * is in transition.
- */
- if (patch->enabled || patch == klp_transition_patch) {
+ if (patch != klp_transition_patch)
+ klp_pre_unpatch_callback(obj);
- if (patch != klp_transition_patch)
- klp_pre_unpatch_callback(obj);
+ pr_notice("reverting patch '%s' on unloading module '%s'\n",
+ patch->mod->name, obj->mod->name);
+ klp_unpatch_object(obj);
- pr_notice("reverting patch '%s' on unloading module '%s'\n",
- patch->mod->name, obj->mod->name);
- klp_unpatch_object(obj);
-
- klp_post_unpatch_callback(obj);
- }
+ klp_post_unpatch_callback(obj);
klp_free_object_loaded(obj);
break;
*/
mod->klp_alive = true;
- list_for_each_entry(patch, &klp_patches, list) {
+ klp_for_each_patch(patch) {
klp_for_each_object(patch, obj) {
if (!klp_is_module(obj) || strcmp(obj->name, mod->name))
continue;
goto err;
}
- /*
- * Only patch the module if the patch is enabled or is
- * in transition.
- */
- if (!patch->enabled && patch != klp_transition_patch)
- break;
-
pr_notice("applying patch '%s' to loading module '%s'\n",
patch->mod->name, obj->mod->name);
#include <linux/livepatch.h>
extern struct mutex klp_mutex;
+extern struct list_head klp_patches;
+
+#define klp_for_each_patch_safe(patch, tmp_patch) \
+ list_for_each_entry_safe(patch, tmp_patch, &klp_patches, list)
+
+#define klp_for_each_patch(patch) \
+ list_for_each_entry(patch, &klp_patches, list)
+
+void klp_free_patch_start(struct klp_patch *patch);
+void klp_discard_replaced_patches(struct klp_patch *new_patch);
+void klp_discard_nops(struct klp_patch *new_patch);
static inline bool klp_is_object_loaded(struct klp_object *obj)
{
static LIST_HEAD(klp_ops);
-struct klp_ops *klp_find_ops(unsigned long old_addr)
+struct klp_ops *klp_find_ops(void *old_func)
{
struct klp_ops *ops;
struct klp_func *func;
list_for_each_entry(ops, &klp_ops, node) {
func = list_first_entry(&ops->func_stack, struct klp_func,
stack_node);
- if (func->old_addr == old_addr)
+ if (func->old_func == old_func)
return ops;
}
}
}
+ /*
+ * NOPs are used to replace existing patches with original code.
+ * Do nothing! Setting pc would cause an infinite loop.
+ */
+ if (func->nop)
+ goto unlock;
+
klp_arch_set_pc(regs, (unsigned long)func->new_func);
+
unlock:
preempt_enable_notrace();
}
if (WARN_ON(!func->patched))
return;
- if (WARN_ON(!func->old_addr))
+ if (WARN_ON(!func->old_func))
return;
- ops = klp_find_ops(func->old_addr);
+ ops = klp_find_ops(func->old_func);
if (WARN_ON(!ops))
return;
if (list_is_singular(&ops->func_stack)) {
unsigned long ftrace_loc;
- ftrace_loc = klp_get_ftrace_location(func->old_addr);
+ ftrace_loc =
+ klp_get_ftrace_location((unsigned long)func->old_func);
if (WARN_ON(!ftrace_loc))
return;
struct klp_ops *ops;
int ret;
- if (WARN_ON(!func->old_addr))
+ if (WARN_ON(!func->old_func))
return -EINVAL;
if (WARN_ON(func->patched))
return -EINVAL;
- ops = klp_find_ops(func->old_addr);
+ ops = klp_find_ops(func->old_func);
if (!ops) {
unsigned long ftrace_loc;
- ftrace_loc = klp_get_ftrace_location(func->old_addr);
+ ftrace_loc =
+ klp_get_ftrace_location((unsigned long)func->old_func);
if (!ftrace_loc) {
pr_err("failed to find location for function '%s'\n",
func->old_name);
return ret;
}
-void klp_unpatch_object(struct klp_object *obj)
+static void __klp_unpatch_object(struct klp_object *obj, bool nops_only)
{
struct klp_func *func;
- klp_for_each_func(obj, func)
+ klp_for_each_func(obj, func) {
+ if (nops_only && !func->nop)
+ continue;
+
if (func->patched)
klp_unpatch_func(func);
+ }
- obj->patched = false;
+ if (obj->dynamic || !nops_only)
+ obj->patched = false;
+}
+
+
+void klp_unpatch_object(struct klp_object *obj)
+{
+ __klp_unpatch_object(obj, false);
}
int klp_patch_object(struct klp_object *obj)
return 0;
}
-void klp_unpatch_objects(struct klp_patch *patch)
+static void __klp_unpatch_objects(struct klp_patch *patch, bool nops_only)
{
struct klp_object *obj;
klp_for_each_object(patch, obj)
if (obj->patched)
- klp_unpatch_object(obj);
+ __klp_unpatch_object(obj, nops_only);
+}
+
+void klp_unpatch_objects(struct klp_patch *patch)
+{
+ __klp_unpatch_objects(patch, false);
+}
+
+void klp_unpatch_objects_dynamic(struct klp_patch *patch)
+{
+ __klp_unpatch_objects(patch, true);
}
* struct klp_ops - structure for tracking registered ftrace ops structs
*
* A single ftrace_ops is shared between all enabled replacement functions
- * (klp_func structs) which have the same old_addr. This allows the switch
+ * (klp_func structs) which have the same old_func. This allows the switch
* between function versions to happen instantaneously by updating the klp_ops
* struct's func_stack list. The winner is the klp_func at the top of the
* func_stack (front of the list).
struct ftrace_ops fops;
};
-struct klp_ops *klp_find_ops(unsigned long old_addr);
+struct klp_ops *klp_find_ops(void *old_func);
int klp_patch_object(struct klp_object *obj);
void klp_unpatch_object(struct klp_object *obj);
void klp_unpatch_objects(struct klp_patch *patch);
+void klp_unpatch_objects_dynamic(struct klp_patch *patch);
#endif /* _LIVEPATCH_PATCH_H */
#define MAX_STACK_ENTRIES 100
#define STACK_ERR_BUF_SIZE 128
+#define SIGNALS_TIMEOUT 15
+
struct klp_patch *klp_transition_patch;
static int klp_target_state = KLP_UNDEFINED;
-static bool klp_forced = false;
+static unsigned int klp_signals_cnt;
/*
* This work can be performed periodically to finish patching or unpatching any
klp_transition_patch->mod->name,
klp_target_state == KLP_PATCHED ? "patching" : "unpatching");
+ if (klp_transition_patch->replace && klp_target_state == KLP_PATCHED) {
+ klp_discard_replaced_patches(klp_transition_patch);
+ klp_discard_nops(klp_transition_patch);
+ }
+
if (klp_target_state == KLP_UNPATCHED) {
/*
* All tasks have transitioned to KLP_UNPATCHED so we can now
pr_notice("'%s': %s complete\n", klp_transition_patch->mod->name,
klp_target_state == KLP_PATCHED ? "patching" : "unpatching");
- /*
- * klp_forced set implies unbounded increase of module's ref count if
- * the module is disabled/enabled in a loop.
- */
- if (!klp_forced && klp_target_state == KLP_UNPATCHED)
- module_put(klp_transition_patch->mod);
-
klp_target_state = KLP_UNDEFINED;
klp_transition_patch = NULL;
}
* Check for the to-be-patched function
* (the previous func).
*/
- ops = klp_find_ops(func->old_addr);
+ ops = klp_find_ops(func->old_func);
if (list_is_singular(&ops->func_stack)) {
/* original function */
- func_addr = func->old_addr;
+ func_addr = (unsigned long)func->old_func;
func_size = func->old_size;
} else {
/* previously patched function */
}
+/*
+ * Sends a fake signal to all non-kthread tasks with TIF_PATCH_PENDING set.
+ * Kthreads with TIF_PATCH_PENDING set are woken up.
+ */
+static void klp_send_signals(void)
+{
+ struct task_struct *g, *task;
+
+ if (klp_signals_cnt == SIGNALS_TIMEOUT)
+ pr_notice("signaling remaining tasks\n");
+
+ read_lock(&tasklist_lock);
+ for_each_process_thread(g, task) {
+ if (!klp_patch_pending(task))
+ continue;
+
+ /*
+ * There is a small race here. We could see TIF_PATCH_PENDING
+ * set and decide to wake up a kthread or send a fake signal.
+ * Meanwhile the task could migrate itself and the action
+ * would be meaningless. It is not serious though.
+ */
+ if (task->flags & PF_KTHREAD) {
+ /*
+ * Wake up a kthread which sleeps interruptedly and
+ * still has not been migrated.
+ */
+ wake_up_state(task, TASK_INTERRUPTIBLE);
+ } else {
+ /*
+ * Send fake signal to all non-kthread tasks which are
+ * still not migrated.
+ */
+ spin_lock_irq(&task->sighand->siglock);
+ signal_wake_up(task, 0);
+ spin_unlock_irq(&task->sighand->siglock);
+ }
+ }
+ read_unlock(&tasklist_lock);
+}
+
/*
* Try to switch all remaining tasks to the target patch state by walking the
* stacks of sleeping tasks and looking for any to-be-patched or
{
unsigned int cpu;
struct task_struct *g, *task;
+ struct klp_patch *patch;
bool complete = true;
WARN_ON_ONCE(klp_target_state == KLP_UNDEFINED);
put_online_cpus();
if (!complete) {
+ if (klp_signals_cnt && !(klp_signals_cnt % SIGNALS_TIMEOUT))
+ klp_send_signals();
+ klp_signals_cnt++;
+
/*
* Some tasks weren't able to be switched over. Try again
* later and/or wait for other methods like kernel exit
}
/* we're done, now cleanup the data structures */
+ patch = klp_transition_patch;
klp_complete_transition();
+
+ /*
+ * It would make more sense to free the patch in
+ * klp_complete_transition() but it is called also
+ * from klp_cancel_transition().
+ */
+ if (!patch->enabled) {
+ klp_free_patch_start(patch);
+ schedule_work(&patch->free_work);
+ }
}
/*
if (task->patch_state != klp_target_state)
set_tsk_thread_flag(task, TIF_PATCH_PENDING);
}
+
+ klp_signals_cnt = 0;
}
/*
/* TIF_PATCH_PENDING gets copied in setup_thread_stack() */
}
-/*
- * Sends a fake signal to all non-kthread tasks with TIF_PATCH_PENDING set.
- * Kthreads with TIF_PATCH_PENDING set are woken up. Only admin can request this
- * action currently.
- */
-void klp_send_signals(void)
-{
- struct task_struct *g, *task;
-
- pr_notice("signaling remaining tasks\n");
-
- read_lock(&tasklist_lock);
- for_each_process_thread(g, task) {
- if (!klp_patch_pending(task))
- continue;
-
- /*
- * There is a small race here. We could see TIF_PATCH_PENDING
- * set and decide to wake up a kthread or send a fake signal.
- * Meanwhile the task could migrate itself and the action
- * would be meaningless. It is not serious though.
- */
- if (task->flags & PF_KTHREAD) {
- /*
- * Wake up a kthread which sleeps interruptedly and
- * still has not been migrated.
- */
- wake_up_state(task, TASK_INTERRUPTIBLE);
- } else {
- /*
- * Send fake signal to all non-kthread tasks which are
- * still not migrated.
- */
- spin_lock_irq(&task->sighand->siglock);
- signal_wake_up(task, 0);
- spin_unlock_irq(&task->sighand->siglock);
- }
- }
- read_unlock(&tasklist_lock);
-}
-
/*
* Drop TIF_PATCH_PENDING of all tasks on admin's request. This forces an
* existing transition to finish.
*/
void klp_force_transition(void)
{
+ struct klp_patch *patch;
struct task_struct *g, *task;
unsigned int cpu;
for_each_possible_cpu(cpu)
klp_update_patch_state(idle_task(cpu));
- klp_forced = true;
+ klp_for_each_patch(patch)
+ patch->forced = true;
}
void klp_start_transition(void);
void klp_try_complete_transition(void);
void klp_reverse_transition(void);
-void klp_send_signals(void);
void klp_force_transition(void);
#endif /* _LIVEPATCH_TRANSITION_H */
If unsure, say N.
+config TEST_LIVEPATCH
+ tristate "Test livepatching"
+ default n
+ depends on DYNAMIC_DEBUG
+ depends on LIVEPATCH
+ depends on m
+ help
+ Test kernel livepatching features for correctness. The tests will
+ load test modules that will be livepatched in various scenarios.
+
+ To run all the livepatching tests:
+
+ make -C tools/testing/selftests TARGETS=livepatch run_tests
+
+ Alternatively, individual tests may be invoked:
+
+ tools/testing/selftests/livepatch/test-callbacks.sh
+ tools/testing/selftests/livepatch/test-livepatch.sh
+ tools/testing/selftests/livepatch/test-shadow-vars.sh
+
+ If unsure, say N.
+
config TEST_OBJAGG
tristate "Perform selftest on object aggreration manager"
default n
Enable this option to test object aggregation manager on boot
(or module load).
- If unsure, say N.
endif # RUNTIME_TESTING_MENU
obj-$(CONFIG_TEST_MEMCAT_P) += test_memcat_p.o
obj-$(CONFIG_TEST_OBJAGG) += test_objagg.o
+obj-$(CONFIG_TEST_LIVEPATCH) += livepatch/
+
ifeq ($(CONFIG_DEBUG_KOBJECT),y)
CFLAGS_kobject.o += -DDEBUG
CFLAGS_kobject_uevent.o += -DDEBUG
--- /dev/null
+# SPDX-License-Identifier: GPL-2.0
+#
+# Makefile for livepatch test code.
+
+obj-$(CONFIG_TEST_LIVEPATCH) += test_klp_atomic_replace.o \
+ test_klp_callbacks_demo.o \
+ test_klp_callbacks_demo2.o \
+ test_klp_callbacks_busy.o \
+ test_klp_callbacks_mod.o \
+ test_klp_livepatch.o \
+ test_klp_shadow_vars.o
+
+# Target modules to be livepatched require CC_FLAGS_FTRACE
+CFLAGS_test_klp_callbacks_busy.o += $(CC_FLAGS_FTRACE)
+CFLAGS_test_klp_callbacks_mod.o += $(CC_FLAGS_FTRACE)
--- /dev/null
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2018 Joe Lawrence <joe.lawrence@redhat.com>
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/livepatch.h>
+
+static int replace;
+module_param(replace, int, 0644);
+MODULE_PARM_DESC(replace, "replace (default=0)");
+
+#include <linux/seq_file.h>
+static int livepatch_meminfo_proc_show(struct seq_file *m, void *v)
+{
+ seq_printf(m, "%s: %s\n", THIS_MODULE->name,
+ "this has been live patched");
+ return 0;
+}
+
+static struct klp_func funcs[] = {
+ {
+ .old_name = "meminfo_proc_show",
+ .new_func = livepatch_meminfo_proc_show,
+ }, {}
+};
+
+static struct klp_object objs[] = {
+ {
+ /* name being NULL means vmlinux */
+ .funcs = funcs,
+ }, {}
+};
+
+static struct klp_patch patch = {
+ .mod = THIS_MODULE,
+ .objs = objs,
+ /* set .replace in the init function below for demo purposes */
+};
+
+static int test_klp_atomic_replace_init(void)
+{
+ patch.replace = replace;
+ return klp_enable_patch(&patch);
+}
+
+static void test_klp_atomic_replace_exit(void)
+{
+}
+
+module_init(test_klp_atomic_replace_init);
+module_exit(test_klp_atomic_replace_exit);
+MODULE_LICENSE("GPL");
+MODULE_INFO(livepatch, "Y");
+MODULE_AUTHOR("Joe Lawrence <joe.lawrence@redhat.com>");
+MODULE_DESCRIPTION("Livepatch test: atomic replace");
--- /dev/null
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2018 Joe Lawrence <joe.lawrence@redhat.com>
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/workqueue.h>
+#include <linux/delay.h>
+
+static int sleep_secs;
+module_param(sleep_secs, int, 0644);
+MODULE_PARM_DESC(sleep_secs, "sleep_secs (default=0)");
+
+static void busymod_work_func(struct work_struct *work);
+static DECLARE_DELAYED_WORK(work, busymod_work_func);
+
+static void busymod_work_func(struct work_struct *work)
+{
+ pr_info("%s, sleeping %d seconds ...\n", __func__, sleep_secs);
+ msleep(sleep_secs * 1000);
+ pr_info("%s exit\n", __func__);
+}
+
+static int test_klp_callbacks_busy_init(void)
+{
+ pr_info("%s\n", __func__);
+ schedule_delayed_work(&work,
+ msecs_to_jiffies(1000 * 0));
+ return 0;
+}
+
+static void test_klp_callbacks_busy_exit(void)
+{
+ cancel_delayed_work_sync(&work);
+ pr_info("%s\n", __func__);
+}
+
+module_init(test_klp_callbacks_busy_init);
+module_exit(test_klp_callbacks_busy_exit);
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Joe Lawrence <joe.lawrence@redhat.com>");
+MODULE_DESCRIPTION("Livepatch test: busy target module");
--- /dev/null
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2018 Joe Lawrence <joe.lawrence@redhat.com>
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/livepatch.h>
+
+static int pre_patch_ret;
+module_param(pre_patch_ret, int, 0644);
+MODULE_PARM_DESC(pre_patch_ret, "pre_patch_ret (default=0)");
+
+static const char *const module_state[] = {
+ [MODULE_STATE_LIVE] = "[MODULE_STATE_LIVE] Normal state",
+ [MODULE_STATE_COMING] = "[MODULE_STATE_COMING] Full formed, running module_init",
+ [MODULE_STATE_GOING] = "[MODULE_STATE_GOING] Going away",
+ [MODULE_STATE_UNFORMED] = "[MODULE_STATE_UNFORMED] Still setting it up",
+};
+
+static void callback_info(const char *callback, struct klp_object *obj)
+{
+ if (obj->mod)
+ pr_info("%s: %s -> %s\n", callback, obj->mod->name,
+ module_state[obj->mod->state]);
+ else
+ pr_info("%s: vmlinux\n", callback);
+}
+
+/* Executed on object patching (ie, patch enablement) */
+static int pre_patch_callback(struct klp_object *obj)
+{
+ callback_info(__func__, obj);
+ return pre_patch_ret;
+}
+
+/* Executed on object unpatching (ie, patch disablement) */
+static void post_patch_callback(struct klp_object *obj)
+{
+ callback_info(__func__, obj);
+}
+
+/* Executed on object unpatching (ie, patch disablement) */
+static void pre_unpatch_callback(struct klp_object *obj)
+{
+ callback_info(__func__, obj);
+}
+
+/* Executed on object unpatching (ie, patch disablement) */
+static void post_unpatch_callback(struct klp_object *obj)
+{
+ callback_info(__func__, obj);
+}
+
+static void patched_work_func(struct work_struct *work)
+{
+ pr_info("%s\n", __func__);
+}
+
+static struct klp_func no_funcs[] = {
+ {}
+};
+
+static struct klp_func busymod_funcs[] = {
+ {
+ .old_name = "busymod_work_func",
+ .new_func = patched_work_func,
+ }, {}
+};
+
+static struct klp_object objs[] = {
+ {
+ .name = NULL, /* vmlinux */
+ .funcs = no_funcs,
+ .callbacks = {
+ .pre_patch = pre_patch_callback,
+ .post_patch = post_patch_callback,
+ .pre_unpatch = pre_unpatch_callback,
+ .post_unpatch = post_unpatch_callback,
+ },
+ }, {
+ .name = "test_klp_callbacks_mod",
+ .funcs = no_funcs,
+ .callbacks = {
+ .pre_patch = pre_patch_callback,
+ .post_patch = post_patch_callback,
+ .pre_unpatch = pre_unpatch_callback,
+ .post_unpatch = post_unpatch_callback,
+ },
+ }, {
+ .name = "test_klp_callbacks_busy",
+ .funcs = busymod_funcs,
+ .callbacks = {
+ .pre_patch = pre_patch_callback,
+ .post_patch = post_patch_callback,
+ .pre_unpatch = pre_unpatch_callback,
+ .post_unpatch = post_unpatch_callback,
+ },
+ }, { }
+};
+
+static struct klp_patch patch = {
+ .mod = THIS_MODULE,
+ .objs = objs,
+};
+
+static int test_klp_callbacks_demo_init(void)
+{
+ return klp_enable_patch(&patch);
+}
+
+static void test_klp_callbacks_demo_exit(void)
+{
+}
+
+module_init(test_klp_callbacks_demo_init);
+module_exit(test_klp_callbacks_demo_exit);
+MODULE_LICENSE("GPL");
+MODULE_INFO(livepatch, "Y");
+MODULE_AUTHOR("Joe Lawrence <joe.lawrence@redhat.com>");
+MODULE_DESCRIPTION("Livepatch test: livepatch demo");
--- /dev/null
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2018 Joe Lawrence <joe.lawrence@redhat.com>
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/livepatch.h>
+
+static int replace;
+module_param(replace, int, 0644);
+MODULE_PARM_DESC(replace, "replace (default=0)");
+
+static const char *const module_state[] = {
+ [MODULE_STATE_LIVE] = "[MODULE_STATE_LIVE] Normal state",
+ [MODULE_STATE_COMING] = "[MODULE_STATE_COMING] Full formed, running module_init",
+ [MODULE_STATE_GOING] = "[MODULE_STATE_GOING] Going away",
+ [MODULE_STATE_UNFORMED] = "[MODULE_STATE_UNFORMED] Still setting it up",
+};
+
+static void callback_info(const char *callback, struct klp_object *obj)
+{
+ if (obj->mod)
+ pr_info("%s: %s -> %s\n", callback, obj->mod->name,
+ module_state[obj->mod->state]);
+ else
+ pr_info("%s: vmlinux\n", callback);
+}
+
+/* Executed on object patching (ie, patch enablement) */
+static int pre_patch_callback(struct klp_object *obj)
+{
+ callback_info(__func__, obj);
+ return 0;
+}
+
+/* Executed on object unpatching (ie, patch disablement) */
+static void post_patch_callback(struct klp_object *obj)
+{
+ callback_info(__func__, obj);
+}
+
+/* Executed on object unpatching (ie, patch disablement) */
+static void pre_unpatch_callback(struct klp_object *obj)
+{
+ callback_info(__func__, obj);
+}
+
+/* Executed on object unpatching (ie, patch disablement) */
+static void post_unpatch_callback(struct klp_object *obj)
+{
+ callback_info(__func__, obj);
+}
+
+static struct klp_func no_funcs[] = {
+ { }
+};
+
+static struct klp_object objs[] = {
+ {
+ .name = NULL, /* vmlinux */
+ .funcs = no_funcs,
+ .callbacks = {
+ .pre_patch = pre_patch_callback,
+ .post_patch = post_patch_callback,
+ .pre_unpatch = pre_unpatch_callback,
+ .post_unpatch = post_unpatch_callback,
+ },
+ }, { }
+};
+
+static struct klp_patch patch = {
+ .mod = THIS_MODULE,
+ .objs = objs,
+ /* set .replace in the init function below for demo purposes */
+};
+
+static int test_klp_callbacks_demo2_init(void)
+{
+ patch.replace = replace;
+ return klp_enable_patch(&patch);
+}
+
+static void test_klp_callbacks_demo2_exit(void)
+{
+}
+
+module_init(test_klp_callbacks_demo2_init);
+module_exit(test_klp_callbacks_demo2_exit);
+MODULE_LICENSE("GPL");
+MODULE_INFO(livepatch, "Y");
+MODULE_AUTHOR("Joe Lawrence <joe.lawrence@redhat.com>");
+MODULE_DESCRIPTION("Livepatch test: livepatch demo2");
--- /dev/null
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2018 Joe Lawrence <joe.lawrence@redhat.com>
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+
+static int test_klp_callbacks_mod_init(void)
+{
+ pr_info("%s\n", __func__);
+ return 0;
+}
+
+static void test_klp_callbacks_mod_exit(void)
+{
+ pr_info("%s\n", __func__);
+}
+
+module_init(test_klp_callbacks_mod_init);
+module_exit(test_klp_callbacks_mod_exit);
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Joe Lawrence <joe.lawrence@redhat.com>");
+MODULE_DESCRIPTION("Livepatch test: target module");
--- /dev/null
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2014 Seth Jennings <sjenning@redhat.com>
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/livepatch.h>
+
+#include <linux/seq_file.h>
+static int livepatch_cmdline_proc_show(struct seq_file *m, void *v)
+{
+ seq_printf(m, "%s: %s\n", THIS_MODULE->name,
+ "this has been live patched");
+ return 0;
+}
+
+static struct klp_func funcs[] = {
+ {
+ .old_name = "cmdline_proc_show",
+ .new_func = livepatch_cmdline_proc_show,
+ }, { }
+};
+
+static struct klp_object objs[] = {
+ {
+ /* name being NULL means vmlinux */
+ .funcs = funcs,
+ }, { }
+};
+
+static struct klp_patch patch = {
+ .mod = THIS_MODULE,
+ .objs = objs,
+};
+
+static int test_klp_livepatch_init(void)
+{
+ return klp_enable_patch(&patch);
+}
+
+static void test_klp_livepatch_exit(void)
+{
+}
+
+module_init(test_klp_livepatch_init);
+module_exit(test_klp_livepatch_exit);
+MODULE_LICENSE("GPL");
+MODULE_INFO(livepatch, "Y");
+MODULE_AUTHOR("Seth Jennings <sjenning@redhat.com>");
+MODULE_DESCRIPTION("Livepatch test: livepatch module");
--- /dev/null
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2018 Joe Lawrence <joe.lawrence@redhat.com>
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/list.h>
+#include <linux/livepatch.h>
+#include <linux/slab.h>
+
+/*
+ * Keep a small list of pointers so that we can print address-agnostic
+ * pointer values. Use a rolling integer count to differentiate the values.
+ * Ironically we could have used the shadow variable API to do this, but
+ * let's not lean too heavily on the very code we're testing.
+ */
+static LIST_HEAD(ptr_list);
+struct shadow_ptr {
+ void *ptr;
+ int id;
+ struct list_head list;
+};
+
+static void free_ptr_list(void)
+{
+ struct shadow_ptr *sp, *tmp_sp;
+
+ list_for_each_entry_safe(sp, tmp_sp, &ptr_list, list) {
+ list_del(&sp->list);
+ kfree(sp);
+ }
+}
+
+static int ptr_id(void *ptr)
+{
+ struct shadow_ptr *sp;
+ static int count;
+
+ list_for_each_entry(sp, &ptr_list, list) {
+ if (sp->ptr == ptr)
+ return sp->id;
+ }
+
+ sp = kmalloc(sizeof(*sp), GFP_ATOMIC);
+ if (!sp)
+ return -ENOMEM;
+ sp->ptr = ptr;
+ sp->id = count++;
+
+ list_add(&sp->list, &ptr_list);
+
+ return sp->id;
+}
+
+/*
+ * Shadow variable wrapper functions that echo the function and arguments
+ * to the kernel log for testing verification. Don't display raw pointers,
+ * but use the ptr_id() value instead.
+ */
+static void *shadow_get(void *obj, unsigned long id)
+{
+ void *ret = klp_shadow_get(obj, id);
+
+ pr_info("klp_%s(obj=PTR%d, id=0x%lx) = PTR%d\n",
+ __func__, ptr_id(obj), id, ptr_id(ret));
+
+ return ret;
+}
+
+static void *shadow_alloc(void *obj, unsigned long id, size_t size,
+ gfp_t gfp_flags, klp_shadow_ctor_t ctor,
+ void *ctor_data)
+{
+ void *ret = klp_shadow_alloc(obj, id, size, gfp_flags, ctor,
+ ctor_data);
+ pr_info("klp_%s(obj=PTR%d, id=0x%lx, size=%zx, gfp_flags=%pGg), ctor=PTR%d, ctor_data=PTR%d = PTR%d\n",
+ __func__, ptr_id(obj), id, size, &gfp_flags, ptr_id(ctor),
+ ptr_id(ctor_data), ptr_id(ret));
+ return ret;
+}
+
+static void *shadow_get_or_alloc(void *obj, unsigned long id, size_t size,
+ gfp_t gfp_flags, klp_shadow_ctor_t ctor,
+ void *ctor_data)
+{
+ void *ret = klp_shadow_get_or_alloc(obj, id, size, gfp_flags, ctor,
+ ctor_data);
+ pr_info("klp_%s(obj=PTR%d, id=0x%lx, size=%zx, gfp_flags=%pGg), ctor=PTR%d, ctor_data=PTR%d = PTR%d\n",
+ __func__, ptr_id(obj), id, size, &gfp_flags, ptr_id(ctor),
+ ptr_id(ctor_data), ptr_id(ret));
+ return ret;
+}
+
+static void shadow_free(void *obj, unsigned long id, klp_shadow_dtor_t dtor)
+{
+ klp_shadow_free(obj, id, dtor);
+ pr_info("klp_%s(obj=PTR%d, id=0x%lx, dtor=PTR%d)\n",
+ __func__, ptr_id(obj), id, ptr_id(dtor));
+}
+
+static void shadow_free_all(unsigned long id, klp_shadow_dtor_t dtor)
+{
+ klp_shadow_free_all(id, dtor);
+ pr_info("klp_%s(id=0x%lx, dtor=PTR%d)\n",
+ __func__, id, ptr_id(dtor));
+}
+
+
+/* Shadow variable constructor - remember simple pointer data */
+static int shadow_ctor(void *obj, void *shadow_data, void *ctor_data)
+{
+ int **shadow_int = shadow_data;
+ *shadow_int = ctor_data;
+ pr_info("%s: PTR%d -> PTR%d\n",
+ __func__, ptr_id(shadow_int), ptr_id(ctor_data));
+
+ return 0;
+}
+
+static void shadow_dtor(void *obj, void *shadow_data)
+{
+ pr_info("%s(obj=PTR%d, shadow_data=PTR%d)\n",
+ __func__, ptr_id(obj), ptr_id(shadow_data));
+}
+
+static int test_klp_shadow_vars_init(void)
+{
+ void *obj = THIS_MODULE;
+ int id = 0x1234;
+ size_t size = sizeof(int *);
+ gfp_t gfp_flags = GFP_KERNEL;
+
+ int var1, var2, var3, var4;
+ int **sv1, **sv2, **sv3, **sv4;
+
+ void *ret;
+
+ ptr_id(NULL);
+ ptr_id(&var1);
+ ptr_id(&var2);
+ ptr_id(&var3);
+ ptr_id(&var4);
+
+ /*
+ * With an empty shadow variable hash table, expect not to find
+ * any matches.
+ */
+ ret = shadow_get(obj, id);
+ if (!ret)
+ pr_info(" got expected NULL result\n");
+
+ /*
+ * Allocate a few shadow variables with different <obj> and <id>.
+ */
+ sv1 = shadow_alloc(obj, id, size, gfp_flags, shadow_ctor, &var1);
+ if (!sv1)
+ return -ENOMEM;
+
+ sv2 = shadow_alloc(obj + 1, id, size, gfp_flags, shadow_ctor, &var2);
+ if (!sv2)
+ return -ENOMEM;
+
+ sv3 = shadow_alloc(obj, id + 1, size, gfp_flags, shadow_ctor, &var3);
+ if (!sv3)
+ return -ENOMEM;
+
+ /*
+ * Verify we can find our new shadow variables and that they point
+ * to expected data.
+ */
+ ret = shadow_get(obj, id);
+ if (!ret)
+ return -EINVAL;
+ if (ret == sv1 && *sv1 == &var1)
+ pr_info(" got expected PTR%d -> PTR%d result\n",
+ ptr_id(sv1), ptr_id(*sv1));
+
+ ret = shadow_get(obj + 1, id);
+ if (!ret)
+ return -EINVAL;
+ if (ret == sv2 && *sv2 == &var2)
+ pr_info(" got expected PTR%d -> PTR%d result\n",
+ ptr_id(sv2), ptr_id(*sv2));
+ ret = shadow_get(obj, id + 1);
+ if (!ret)
+ return -EINVAL;
+ if (ret == sv3 && *sv3 == &var3)
+ pr_info(" got expected PTR%d -> PTR%d result\n",
+ ptr_id(sv3), ptr_id(*sv3));
+
+ /*
+ * Allocate or get a few more, this time with the same <obj>, <id>.
+ * The second invocation should return the same shadow var.
+ */
+ sv4 = shadow_get_or_alloc(obj + 2, id, size, gfp_flags, shadow_ctor, &var4);
+ if (!sv4)
+ return -ENOMEM;
+
+ ret = shadow_get_or_alloc(obj + 2, id, size, gfp_flags, shadow_ctor, &var4);
+ if (!ret)
+ return -EINVAL;
+ if (ret == sv4 && *sv4 == &var4)
+ pr_info(" got expected PTR%d -> PTR%d result\n",
+ ptr_id(sv4), ptr_id(*sv4));
+
+ /*
+ * Free the <obj=*, id> shadow variables and check that we can no
+ * longer find them.
+ */
+ shadow_free(obj, id, shadow_dtor); /* sv1 */
+ ret = shadow_get(obj, id);
+ if (!ret)
+ pr_info(" got expected NULL result\n");
+
+ shadow_free(obj + 1, id, shadow_dtor); /* sv2 */
+ ret = shadow_get(obj + 1, id);
+ if (!ret)
+ pr_info(" got expected NULL result\n");
+
+ shadow_free(obj + 2, id, shadow_dtor); /* sv4 */
+ ret = shadow_get(obj + 2, id);
+ if (!ret)
+ pr_info(" got expected NULL result\n");
+
+ /*
+ * We should still find an <id+1> variable.
+ */
+ ret = shadow_get(obj, id + 1);
+ if (!ret)
+ return -EINVAL;
+ if (ret == sv3 && *sv3 == &var3)
+ pr_info(" got expected PTR%d -> PTR%d result\n",
+ ptr_id(sv3), ptr_id(*sv3));
+
+ /*
+ * Free all the <id+1> variables, too.
+ */
+ shadow_free_all(id + 1, shadow_dtor); /* sv3 */
+ ret = shadow_get(obj, id);
+ if (!ret)
+ pr_info(" shadow_get() got expected NULL result\n");
+
+
+ free_ptr_list();
+
+ return 0;
+}
+
+static void test_klp_shadow_vars_exit(void)
+{
+}
+
+module_init(test_klp_shadow_vars_init);
+module_exit(test_klp_shadow_vars_exit);
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Joe Lawrence <joe.lawrence@redhat.com>");
+MODULE_DESCRIPTION("Livepatch test: shadow variables");
static int livepatch_callbacks_demo_init(void)
{
- int ret;
-
- ret = klp_register_patch(&patch);
- if (ret)
- return ret;
- ret = klp_enable_patch(&patch);
- if (ret) {
- WARN_ON(klp_unregister_patch(&patch));
- return ret;
- }
- return 0;
+ return klp_enable_patch(&patch);
}
static void livepatch_callbacks_demo_exit(void)
{
- WARN_ON(klp_unregister_patch(&patch));
}
module_init(livepatch_callbacks_demo_init);
static int livepatch_init(void)
{
- int ret;
-
- ret = klp_register_patch(&patch);
- if (ret)
- return ret;
- ret = klp_enable_patch(&patch);
- if (ret) {
- WARN_ON(klp_unregister_patch(&patch));
- return ret;
- }
- return 0;
+ return klp_enable_patch(&patch);
}
static void livepatch_exit(void)
{
- WARN_ON(klp_unregister_patch(&patch));
}
module_init(livepatch_init);
return 0;
}
-struct dummy *livepatch_fix1_dummy_alloc(void)
+static struct dummy *livepatch_fix1_dummy_alloc(void)
{
struct dummy *d;
void *leak;
__func__, d, *shadow_leak);
}
-void livepatch_fix1_dummy_free(struct dummy *d)
+static void livepatch_fix1_dummy_free(struct dummy *d)
{
void **shadow_leak;
static int livepatch_shadow_fix1_init(void)
{
- int ret;
-
- ret = klp_register_patch(&patch);
- if (ret)
- return ret;
- ret = klp_enable_patch(&patch);
- if (ret) {
- WARN_ON(klp_unregister_patch(&patch));
- return ret;
- }
- return 0;
+ return klp_enable_patch(&patch);
}
static void livepatch_shadow_fix1_exit(void)
{
/* Cleanup any existing SV_LEAK shadow variables */
klp_shadow_free_all(SV_LEAK, livepatch_fix1_dummy_leak_dtor);
-
- WARN_ON(klp_unregister_patch(&patch));
}
module_init(livepatch_shadow_fix1_init);
unsigned long jiffies_expire;
};
-bool livepatch_fix2_dummy_check(struct dummy *d, unsigned long jiffies)
+static bool livepatch_fix2_dummy_check(struct dummy *d, unsigned long jiffies)
{
int *shadow_count;
__func__, d, *shadow_leak);
}
-void livepatch_fix2_dummy_free(struct dummy *d)
+static void livepatch_fix2_dummy_free(struct dummy *d)
{
void **shadow_leak;
int *shadow_count;
static int livepatch_shadow_fix2_init(void)
{
- int ret;
-
- ret = klp_register_patch(&patch);
- if (ret)
- return ret;
- ret = klp_enable_patch(&patch);
- if (ret) {
- WARN_ON(klp_unregister_patch(&patch));
- return ret;
- }
- return 0;
+ return klp_enable_patch(&patch);
}
static void livepatch_shadow_fix2_exit(void)
{
/* Cleanup any existing SV_COUNTER shadow variables */
klp_shadow_free_all(SV_COUNTER, NULL);
-
- WARN_ON(klp_unregister_patch(&patch));
}
module_init(livepatch_shadow_fix2_init);
* Keep a list of all the dummies so we can clean up any residual ones
* on module exit
*/
-LIST_HEAD(dummy_list);
-DEFINE_MUTEX(dummy_list_mutex);
+static LIST_HEAD(dummy_list);
+static DEFINE_MUTEX(dummy_list_mutex);
struct dummy {
struct list_head list;
unsigned long jiffies_expire;
};
-noinline struct dummy *dummy_alloc(void)
+static __used noinline struct dummy *dummy_alloc(void)
{
struct dummy *d;
void *leak;
return d;
}
-noinline void dummy_free(struct dummy *d)
+static __used noinline void dummy_free(struct dummy *d)
{
pr_info("%s: dummy @ %p, expired = %lx\n",
__func__, d, d->jiffies_expire);
kfree(d);
}
-noinline bool dummy_check(struct dummy *d, unsigned long jiffies)
+static __used noinline bool dummy_check(struct dummy *d,
+ unsigned long jiffies)
{
return time_after(jiffies, d->jiffies_expire);
}
TARGETS += kcmp
TARGETS += kvm
TARGETS += lib
+TARGETS += livepatch
TARGETS += membarrier
TARGETS += memfd
TARGETS += memory-hotplug
--- /dev/null
+# SPDX-License-Identifier: GPL-2.0
+
+TEST_GEN_PROGS := \
+ test-livepatch.sh \
+ test-callbacks.sh \
+ test-shadow-vars.sh
+
+include ../lib.mk
--- /dev/null
+====================
+Livepatch Self Tests
+====================
+
+This is a small set of sanity tests for the kernel livepatching.
+
+The test suite loads and unloads several test kernel modules to verify
+livepatch behavior. Debug information is logged to the kernel's message
+buffer and parsed for expected messages. (Note: the tests will clear
+the message buffer between individual tests.)
+
+
+Config
+------
+
+Set these config options and their prerequisites:
+
+CONFIG_LIVEPATCH=y
+CONFIG_TEST_LIVEPATCH=m
+
+
+Running the tests
+-----------------
+
+Test kernel modules are built as part of lib/ (make modules) and need to
+be installed (make modules_install) as the test scripts will modprobe
+them.
+
+To run the livepatch selftests, from the top of the kernel source tree:
+
+ % make -C tools/testing/selftests TARGETS=livepatch run_tests
+
+
+Adding tests
+------------
+
+See the common functions.sh file for the existing collection of utility
+functions, most importantly set_dynamic_debug() and check_result(). The
+latter function greps the kernel's ring buffer for "livepatch:" and
+"test_klp" strings, so tests be sure to include one of those strings for
+result comparison. Other utility functions include general module
+loading and livepatch loading helpers (waiting for patch transitions,
+sysfs entries, etc.)
--- /dev/null
+CONFIG_TEST_LIVEPATCH=m
--- /dev/null
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (C) 2018 Joe Lawrence <joe.lawrence@redhat.com>
+
+# Shell functions for the rest of the scripts.
+
+MAX_RETRIES=600
+RETRY_INTERVAL=".1" # seconds
+
+# log(msg) - write message to kernel log
+# msg - insightful words
+function log() {
+ echo "$1" > /dev/kmsg
+}
+
+# die(msg) - game over, man
+# msg - dying words
+function die() {
+ log "ERROR: $1"
+ echo "ERROR: $1" >&2
+ exit 1
+}
+
+# set_dynamic_debug() - setup kernel dynamic debug
+# TODO - push and pop this config?
+function set_dynamic_debug() {
+ cat << EOF > /sys/kernel/debug/dynamic_debug/control
+file kernel/livepatch/* +p
+func klp_try_switch_task -p
+EOF
+}
+
+# loop_until(cmd) - loop a command until it is successful or $MAX_RETRIES,
+# sleep $RETRY_INTERVAL between attempts
+# cmd - command and its arguments to run
+function loop_until() {
+ local cmd="$*"
+ local i=0
+ while true; do
+ eval "$cmd" && return 0
+ [[ $((i++)) -eq $MAX_RETRIES ]] && return 1
+ sleep $RETRY_INTERVAL
+ done
+}
+
+function is_livepatch_mod() {
+ local mod="$1"
+
+ if [[ $(modinfo "$mod" | awk '/^livepatch:/{print $NF}') == "Y" ]]; then
+ return 0
+ fi
+
+ return 1
+}
+
+function __load_mod() {
+ local mod="$1"; shift
+
+ local msg="% modprobe $mod $*"
+ log "${msg%% }"
+ ret=$(modprobe "$mod" "$@" 2>&1)
+ if [[ "$ret" != "" ]]; then
+ die "$ret"
+ fi
+
+ # Wait for module in sysfs ...
+ loop_until '[[ -e "/sys/module/$mod" ]]' ||
+ die "failed to load module $mod"
+}
+
+
+# load_mod(modname, params) - load a kernel module
+# modname - module name to load
+# params - module parameters to pass to modprobe
+function load_mod() {
+ local mod="$1"; shift
+
+ is_livepatch_mod "$mod" &&
+ die "use load_lp() to load the livepatch module $mod"
+
+ __load_mod "$mod" "$@"
+}
+
+# load_lp_nowait(modname, params) - load a kernel module with a livepatch
+# but do not wait on until the transition finishes
+# modname - module name to load
+# params - module parameters to pass to modprobe
+function load_lp_nowait() {
+ local mod="$1"; shift
+
+ is_livepatch_mod "$mod" ||
+ die "module $mod is not a livepatch"
+
+ __load_mod "$mod" "$@"
+
+ # Wait for livepatch in sysfs ...
+ loop_until '[[ -e "/sys/kernel/livepatch/$mod" ]]' ||
+ die "failed to load module $mod (sysfs)"
+}
+
+# load_lp(modname, params) - load a kernel module with a livepatch
+# modname - module name to load
+# params - module parameters to pass to modprobe
+function load_lp() {
+ local mod="$1"; shift
+
+ load_lp_nowait "$mod" "$@"
+
+ # Wait until the transition finishes ...
+ loop_until 'grep -q '^0$' /sys/kernel/livepatch/$mod/transition' ||
+ die "failed to complete transition"
+}
+
+# load_failing_mod(modname, params) - load a kernel module, expect to fail
+# modname - module name to load
+# params - module parameters to pass to modprobe
+function load_failing_mod() {
+ local mod="$1"; shift
+
+ local msg="% modprobe $mod $*"
+ log "${msg%% }"
+ ret=$(modprobe "$mod" "$@" 2>&1)
+ if [[ "$ret" == "" ]]; then
+ die "$mod unexpectedly loaded"
+ fi
+ log "$ret"
+}
+
+# unload_mod(modname) - unload a kernel module
+# modname - module name to unload
+function unload_mod() {
+ local mod="$1"
+
+ # Wait for module reference count to clear ...
+ loop_until '[[ $(cat "/sys/module/$mod/refcnt") == "0" ]]' ||
+ die "failed to unload module $mod (refcnt)"
+
+ log "% rmmod $mod"
+ ret=$(rmmod "$mod" 2>&1)
+ if [[ "$ret" != "" ]]; then
+ die "$ret"
+ fi
+
+ # Wait for module in sysfs ...
+ loop_until '[[ ! -e "/sys/module/$mod" ]]' ||
+ die "failed to unload module $mod (/sys/module)"
+}
+
+# unload_lp(modname) - unload a kernel module with a livepatch
+# modname - module name to unload
+function unload_lp() {
+ unload_mod "$1"
+}
+
+# disable_lp(modname) - disable a livepatch
+# modname - module name to unload
+function disable_lp() {
+ local mod="$1"
+
+ log "% echo 0 > /sys/kernel/livepatch/$mod/enabled"
+ echo 0 > /sys/kernel/livepatch/"$mod"/enabled
+
+ # Wait until the transition finishes and the livepatch gets
+ # removed from sysfs...
+ loop_until '[[ ! -e "/sys/kernel/livepatch/$mod" ]]' ||
+ die "failed to disable livepatch $mod"
+}
+
+# set_pre_patch_ret(modname, pre_patch_ret)
+# modname - module name to set
+# pre_patch_ret - new pre_patch_ret value
+function set_pre_patch_ret {
+ local mod="$1"; shift
+ local ret="$1"
+
+ log "% echo $ret > /sys/module/$mod/parameters/pre_patch_ret"
+ echo "$ret" > /sys/module/"$mod"/parameters/pre_patch_ret
+
+ # Wait for sysfs value to hold ...
+ loop_until '[[ $(cat "/sys/module/$mod/parameters/pre_patch_ret") == "$ret" ]]' ||
+ die "failed to set pre_patch_ret parameter for $mod module"
+}
+
+# check_result() - verify dmesg output
+# TODO - better filter, out of order msgs, etc?
+function check_result {
+ local expect="$*"
+ local result
+
+ result=$(dmesg | grep -v 'tainting' | grep -e 'livepatch:' -e 'test_klp' | sed 's/^\[[ 0-9.]*\] //')
+
+ if [[ "$expect" == "$result" ]] ; then
+ echo "ok"
+ else
+ echo -e "not ok\n\n$(diff -upr --label expected --label result <(echo "$expect") <(echo "$result"))\n"
+ die "livepatch kselftest(s) failed"
+ fi
+}
--- /dev/null
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (C) 2018 Joe Lawrence <joe.lawrence@redhat.com>
+
+. $(dirname $0)/functions.sh
+
+MOD_LIVEPATCH=test_klp_callbacks_demo
+MOD_LIVEPATCH2=test_klp_callbacks_demo2
+MOD_TARGET=test_klp_callbacks_mod
+MOD_TARGET_BUSY=test_klp_callbacks_busy
+
+set_dynamic_debug
+
+
+# TEST: target module before livepatch
+#
+# Test a combination of loading a kernel module and a livepatch that
+# patches a function in the first module. Load the target module
+# before the livepatch module. Unload them in the same order.
+#
+# - On livepatch enable, before the livepatch transition starts,
+# pre-patch callbacks are executed for vmlinux and $MOD_TARGET (those
+# klp_objects currently loaded). After klp_objects are patched
+# according to the klp_patch, their post-patch callbacks run and the
+# transition completes.
+#
+# - Similarly, on livepatch disable, pre-patch callbacks run before the
+# unpatching transition starts. klp_objects are reverted, post-patch
+# callbacks execute and the transition completes.
+
+echo -n "TEST: target module before livepatch ... "
+dmesg -C
+
+load_mod $MOD_TARGET
+load_lp $MOD_LIVEPATCH
+disable_lp $MOD_LIVEPATCH
+unload_lp $MOD_LIVEPATCH
+unload_mod $MOD_TARGET
+
+check_result "% modprobe $MOD_TARGET
+$MOD_TARGET: ${MOD_TARGET}_init
+% modprobe $MOD_LIVEPATCH
+livepatch: enabling patch '$MOD_LIVEPATCH'
+livepatch: '$MOD_LIVEPATCH': initializing patching transition
+$MOD_LIVEPATCH: pre_patch_callback: vmlinux
+$MOD_LIVEPATCH: pre_patch_callback: $MOD_TARGET -> [MODULE_STATE_LIVE] Normal state
+livepatch: '$MOD_LIVEPATCH': starting patching transition
+livepatch: '$MOD_LIVEPATCH': completing patching transition
+$MOD_LIVEPATCH: post_patch_callback: vmlinux
+$MOD_LIVEPATCH: post_patch_callback: $MOD_TARGET -> [MODULE_STATE_LIVE] Normal state
+livepatch: '$MOD_LIVEPATCH': patching complete
+% echo 0 > /sys/kernel/livepatch/$MOD_LIVEPATCH/enabled
+livepatch: '$MOD_LIVEPATCH': initializing unpatching transition
+$MOD_LIVEPATCH: pre_unpatch_callback: vmlinux
+$MOD_LIVEPATCH: pre_unpatch_callback: $MOD_TARGET -> [MODULE_STATE_LIVE] Normal state
+livepatch: '$MOD_LIVEPATCH': starting unpatching transition
+livepatch: '$MOD_LIVEPATCH': completing unpatching transition
+$MOD_LIVEPATCH: post_unpatch_callback: vmlinux
+$MOD_LIVEPATCH: post_unpatch_callback: $MOD_TARGET -> [MODULE_STATE_LIVE] Normal state
+livepatch: '$MOD_LIVEPATCH': unpatching complete
+% rmmod $MOD_LIVEPATCH
+% rmmod $MOD_TARGET
+$MOD_TARGET: ${MOD_TARGET}_exit"
+
+
+# TEST: module_coming notifier
+#
+# This test is similar to the previous test, but (un)load the livepatch
+# module before the target kernel module. This tests the livepatch
+# core's module_coming handler.
+#
+# - On livepatch enable, only pre/post-patch callbacks are executed for
+# currently loaded klp_objects, in this case, vmlinux.
+#
+# - When a targeted module is subsequently loaded, only its
+# pre/post-patch callbacks are executed.
+#
+# - On livepatch disable, all currently loaded klp_objects' (vmlinux and
+# $MOD_TARGET) pre/post-unpatch callbacks are executed.
+
+echo -n "TEST: module_coming notifier ... "
+dmesg -C
+
+load_lp $MOD_LIVEPATCH
+load_mod $MOD_TARGET
+disable_lp $MOD_LIVEPATCH
+unload_lp $MOD_LIVEPATCH
+unload_mod $MOD_TARGET
+
+check_result "% modprobe $MOD_LIVEPATCH
+livepatch: enabling patch '$MOD_LIVEPATCH'
+livepatch: '$MOD_LIVEPATCH': initializing patching transition
+$MOD_LIVEPATCH: pre_patch_callback: vmlinux
+livepatch: '$MOD_LIVEPATCH': starting patching transition
+livepatch: '$MOD_LIVEPATCH': completing patching transition
+$MOD_LIVEPATCH: post_patch_callback: vmlinux
+livepatch: '$MOD_LIVEPATCH': patching complete
+% modprobe $MOD_TARGET
+livepatch: applying patch '$MOD_LIVEPATCH' to loading module '$MOD_TARGET'
+$MOD_LIVEPATCH: pre_patch_callback: $MOD_TARGET -> [MODULE_STATE_COMING] Full formed, running module_init
+$MOD_LIVEPATCH: post_patch_callback: $MOD_TARGET -> [MODULE_STATE_COMING] Full formed, running module_init
+$MOD_TARGET: ${MOD_TARGET}_init
+% echo 0 > /sys/kernel/livepatch/$MOD_LIVEPATCH/enabled
+livepatch: '$MOD_LIVEPATCH': initializing unpatching transition
+$MOD_LIVEPATCH: pre_unpatch_callback: vmlinux
+$MOD_LIVEPATCH: pre_unpatch_callback: $MOD_TARGET -> [MODULE_STATE_LIVE] Normal state
+livepatch: '$MOD_LIVEPATCH': starting unpatching transition
+livepatch: '$MOD_LIVEPATCH': completing unpatching transition
+$MOD_LIVEPATCH: post_unpatch_callback: vmlinux
+$MOD_LIVEPATCH: post_unpatch_callback: $MOD_TARGET -> [MODULE_STATE_LIVE] Normal state
+livepatch: '$MOD_LIVEPATCH': unpatching complete
+% rmmod $MOD_LIVEPATCH
+% rmmod $MOD_TARGET
+$MOD_TARGET: ${MOD_TARGET}_exit"
+
+
+# TEST: module_going notifier
+#
+# Test loading the livepatch after a targeted kernel module, then unload
+# the kernel module before disabling the livepatch. This tests the
+# livepatch core's module_going handler.
+#
+# - First load a target module, then the livepatch.
+#
+# - When a target module is unloaded, the livepatch is only reverted
+# from that klp_object ($MOD_TARGET). As such, only its pre and
+# post-unpatch callbacks are executed when this occurs.
+#
+# - When the livepatch is disabled, pre and post-unpatch callbacks are
+# run for the remaining klp_object, vmlinux.
+
+echo -n "TEST: module_going notifier ... "
+dmesg -C
+
+load_mod $MOD_TARGET
+load_lp $MOD_LIVEPATCH
+unload_mod $MOD_TARGET
+disable_lp $MOD_LIVEPATCH
+unload_lp $MOD_LIVEPATCH
+
+check_result "% modprobe $MOD_TARGET
+$MOD_TARGET: ${MOD_TARGET}_init
+% modprobe $MOD_LIVEPATCH
+livepatch: enabling patch '$MOD_LIVEPATCH'
+livepatch: '$MOD_LIVEPATCH': initializing patching transition
+$MOD_LIVEPATCH: pre_patch_callback: vmlinux
+$MOD_LIVEPATCH: pre_patch_callback: $MOD_TARGET -> [MODULE_STATE_LIVE] Normal state
+livepatch: '$MOD_LIVEPATCH': starting patching transition
+livepatch: '$MOD_LIVEPATCH': completing patching transition
+$MOD_LIVEPATCH: post_patch_callback: vmlinux
+$MOD_LIVEPATCH: post_patch_callback: $MOD_TARGET -> [MODULE_STATE_LIVE] Normal state
+livepatch: '$MOD_LIVEPATCH': patching complete
+% rmmod $MOD_TARGET
+$MOD_TARGET: ${MOD_TARGET}_exit
+$MOD_LIVEPATCH: pre_unpatch_callback: $MOD_TARGET -> [MODULE_STATE_GOING] Going away
+livepatch: reverting patch '$MOD_LIVEPATCH' on unloading module '$MOD_TARGET'
+$MOD_LIVEPATCH: post_unpatch_callback: $MOD_TARGET -> [MODULE_STATE_GOING] Going away
+% echo 0 > /sys/kernel/livepatch/$MOD_LIVEPATCH/enabled
+livepatch: '$MOD_LIVEPATCH': initializing unpatching transition
+$MOD_LIVEPATCH: pre_unpatch_callback: vmlinux
+livepatch: '$MOD_LIVEPATCH': starting unpatching transition
+livepatch: '$MOD_LIVEPATCH': completing unpatching transition
+$MOD_LIVEPATCH: post_unpatch_callback: vmlinux
+livepatch: '$MOD_LIVEPATCH': unpatching complete
+% rmmod $MOD_LIVEPATCH"
+
+
+# TEST: module_coming and module_going notifiers
+#
+# This test is similar to the previous test, however the livepatch is
+# loaded first. This tests the livepatch core's module_coming and
+# module_going handlers.
+#
+# - First load the livepatch.
+#
+# - When a targeted kernel module is subsequently loaded, only its
+# pre/post-patch callbacks are executed.
+#
+# - When the target module is unloaded, the livepatch is only reverted
+# from the $MOD_TARGET klp_object. As such, only pre and
+# post-unpatch callbacks are executed when this occurs.
+
+echo -n "TEST: module_coming and module_going notifiers ... "
+dmesg -C
+
+load_lp $MOD_LIVEPATCH
+load_mod $MOD_TARGET
+unload_mod $MOD_TARGET
+disable_lp $MOD_LIVEPATCH
+unload_lp $MOD_LIVEPATCH
+
+check_result "% modprobe $MOD_LIVEPATCH
+livepatch: enabling patch '$MOD_LIVEPATCH'
+livepatch: '$MOD_LIVEPATCH': initializing patching transition
+$MOD_LIVEPATCH: pre_patch_callback: vmlinux
+livepatch: '$MOD_LIVEPATCH': starting patching transition
+livepatch: '$MOD_LIVEPATCH': completing patching transition
+$MOD_LIVEPATCH: post_patch_callback: vmlinux
+livepatch: '$MOD_LIVEPATCH': patching complete
+% modprobe $MOD_TARGET
+livepatch: applying patch '$MOD_LIVEPATCH' to loading module '$MOD_TARGET'
+$MOD_LIVEPATCH: pre_patch_callback: $MOD_TARGET -> [MODULE_STATE_COMING] Full formed, running module_init
+$MOD_LIVEPATCH: post_patch_callback: $MOD_TARGET -> [MODULE_STATE_COMING] Full formed, running module_init
+$MOD_TARGET: ${MOD_TARGET}_init
+% rmmod $MOD_TARGET
+$MOD_TARGET: ${MOD_TARGET}_exit
+$MOD_LIVEPATCH: pre_unpatch_callback: $MOD_TARGET -> [MODULE_STATE_GOING] Going away
+livepatch: reverting patch '$MOD_LIVEPATCH' on unloading module '$MOD_TARGET'
+$MOD_LIVEPATCH: post_unpatch_callback: $MOD_TARGET -> [MODULE_STATE_GOING] Going away
+% echo 0 > /sys/kernel/livepatch/$MOD_LIVEPATCH/enabled
+livepatch: '$MOD_LIVEPATCH': initializing unpatching transition
+$MOD_LIVEPATCH: pre_unpatch_callback: vmlinux
+livepatch: '$MOD_LIVEPATCH': starting unpatching transition
+livepatch: '$MOD_LIVEPATCH': completing unpatching transition
+$MOD_LIVEPATCH: post_unpatch_callback: vmlinux
+livepatch: '$MOD_LIVEPATCH': unpatching complete
+% rmmod $MOD_LIVEPATCH"
+
+
+# TEST: target module not present
+#
+# A simple test of loading a livepatch without one of its patch target
+# klp_objects ever loaded ($MOD_TARGET).
+#
+# - Load the livepatch.
+#
+# - As expected, only pre/post-(un)patch handlers are executed for
+# vmlinux.
+
+echo -n "TEST: target module not present ... "
+dmesg -C
+
+load_lp $MOD_LIVEPATCH
+disable_lp $MOD_LIVEPATCH
+unload_lp $MOD_LIVEPATCH
+
+check_result "% modprobe $MOD_LIVEPATCH
+livepatch: enabling patch '$MOD_LIVEPATCH'
+livepatch: '$MOD_LIVEPATCH': initializing patching transition
+$MOD_LIVEPATCH: pre_patch_callback: vmlinux
+livepatch: '$MOD_LIVEPATCH': starting patching transition
+livepatch: '$MOD_LIVEPATCH': completing patching transition
+$MOD_LIVEPATCH: post_patch_callback: vmlinux
+livepatch: '$MOD_LIVEPATCH': patching complete
+% echo 0 > /sys/kernel/livepatch/$MOD_LIVEPATCH/enabled
+livepatch: '$MOD_LIVEPATCH': initializing unpatching transition
+$MOD_LIVEPATCH: pre_unpatch_callback: vmlinux
+livepatch: '$MOD_LIVEPATCH': starting unpatching transition
+livepatch: '$MOD_LIVEPATCH': completing unpatching transition
+$MOD_LIVEPATCH: post_unpatch_callback: vmlinux
+livepatch: '$MOD_LIVEPATCH': unpatching complete
+% rmmod $MOD_LIVEPATCH"
+
+
+# TEST: pre-patch callback -ENODEV
+#
+# Test a scenario where a vmlinux pre-patch callback returns a non-zero
+# status (ie, failure).
+#
+# - First load a target module.
+#
+# - Load the livepatch module, setting its 'pre_patch_ret' value to -19
+# (-ENODEV). When its vmlinux pre-patch callback executes, this
+# status code will propagate back to the module-loading subsystem.
+# The result is that the insmod command refuses to load the livepatch
+# module.
+
+echo -n "TEST: pre-patch callback -ENODEV ... "
+dmesg -C
+
+load_mod $MOD_TARGET
+load_failing_mod $MOD_LIVEPATCH pre_patch_ret=-19
+unload_mod $MOD_TARGET
+
+check_result "% modprobe $MOD_TARGET
+$MOD_TARGET: ${MOD_TARGET}_init
+% modprobe $MOD_LIVEPATCH pre_patch_ret=-19
+livepatch: enabling patch '$MOD_LIVEPATCH'
+livepatch: '$MOD_LIVEPATCH': initializing patching transition
+test_klp_callbacks_demo: pre_patch_callback: vmlinux
+livepatch: pre-patch callback failed for object 'vmlinux'
+livepatch: failed to enable patch '$MOD_LIVEPATCH'
+livepatch: '$MOD_LIVEPATCH': canceling patching transition, going to unpatch
+livepatch: '$MOD_LIVEPATCH': completing unpatching transition
+livepatch: '$MOD_LIVEPATCH': unpatching complete
+modprobe: ERROR: could not insert '$MOD_LIVEPATCH': No such device
+% rmmod $MOD_TARGET
+$MOD_TARGET: ${MOD_TARGET}_exit"
+
+
+# TEST: module_coming + pre-patch callback -ENODEV
+#
+# Similar to the previous test, setup a livepatch such that its vmlinux
+# pre-patch callback returns success. However, when a targeted kernel
+# module is later loaded, have the livepatch return a failing status
+# code.
+#
+# - Load the livepatch, vmlinux pre-patch callback succeeds.
+#
+# - Set a trap so subsequent pre-patch callbacks to this livepatch will
+# return -ENODEV.
+#
+# - The livepatch pre-patch callback for subsequently loaded target
+# modules will return failure, so the module loader refuses to load
+# the kernel module. No post-patch or pre/post-unpatch callbacks are
+# executed for this klp_object.
+#
+# - Pre/post-unpatch callbacks are run for the vmlinux klp_object.
+
+echo -n "TEST: module_coming + pre-patch callback -ENODEV ... "
+dmesg -C
+
+load_lp $MOD_LIVEPATCH
+set_pre_patch_ret $MOD_LIVEPATCH -19
+load_failing_mod $MOD_TARGET
+disable_lp $MOD_LIVEPATCH
+unload_lp $MOD_LIVEPATCH
+
+check_result "% modprobe $MOD_LIVEPATCH
+livepatch: enabling patch '$MOD_LIVEPATCH'
+livepatch: '$MOD_LIVEPATCH': initializing patching transition
+$MOD_LIVEPATCH: pre_patch_callback: vmlinux
+livepatch: '$MOD_LIVEPATCH': starting patching transition
+livepatch: '$MOD_LIVEPATCH': completing patching transition
+$MOD_LIVEPATCH: post_patch_callback: vmlinux
+livepatch: '$MOD_LIVEPATCH': patching complete
+% echo -19 > /sys/module/$MOD_LIVEPATCH/parameters/pre_patch_ret
+% modprobe $MOD_TARGET
+livepatch: applying patch '$MOD_LIVEPATCH' to loading module '$MOD_TARGET'
+$MOD_LIVEPATCH: pre_patch_callback: $MOD_TARGET -> [MODULE_STATE_COMING] Full formed, running module_init
+livepatch: pre-patch callback failed for object '$MOD_TARGET'
+livepatch: patch '$MOD_LIVEPATCH' failed for module '$MOD_TARGET', refusing to load module '$MOD_TARGET'
+modprobe: ERROR: could not insert '$MOD_TARGET': No such device
+% echo 0 > /sys/kernel/livepatch/$MOD_LIVEPATCH/enabled
+livepatch: '$MOD_LIVEPATCH': initializing unpatching transition
+$MOD_LIVEPATCH: pre_unpatch_callback: vmlinux
+livepatch: '$MOD_LIVEPATCH': starting unpatching transition
+livepatch: '$MOD_LIVEPATCH': completing unpatching transition
+$MOD_LIVEPATCH: post_unpatch_callback: vmlinux
+livepatch: '$MOD_LIVEPATCH': unpatching complete
+% rmmod $MOD_LIVEPATCH"
+
+
+# TEST: multiple target modules
+#
+# Test loading multiple targeted kernel modules. This test-case is
+# mainly for comparing with the next test-case.
+#
+# - Load a target "busy" kernel module which kicks off a worker function
+# that immediately exits.
+#
+# - Proceed with loading the livepatch and another ordinary target
+# module. Post-patch callbacks are executed and the transition
+# completes quickly.
+
+echo -n "TEST: multiple target modules ... "
+dmesg -C
+
+load_mod $MOD_TARGET_BUSY sleep_secs=0
+# give $MOD_TARGET_BUSY::busymod_work_func() a chance to run
+sleep 5
+load_lp $MOD_LIVEPATCH
+load_mod $MOD_TARGET
+unload_mod $MOD_TARGET
+disable_lp $MOD_LIVEPATCH
+unload_lp $MOD_LIVEPATCH
+unload_mod $MOD_TARGET_BUSY
+
+check_result "% modprobe $MOD_TARGET_BUSY sleep_secs=0
+$MOD_TARGET_BUSY: ${MOD_TARGET_BUSY}_init
+$MOD_TARGET_BUSY: busymod_work_func, sleeping 0 seconds ...
+$MOD_TARGET_BUSY: busymod_work_func exit
+% modprobe $MOD_LIVEPATCH
+livepatch: enabling patch '$MOD_LIVEPATCH'
+livepatch: '$MOD_LIVEPATCH': initializing patching transition
+$MOD_LIVEPATCH: pre_patch_callback: vmlinux
+$MOD_LIVEPATCH: pre_patch_callback: $MOD_TARGET_BUSY -> [MODULE_STATE_LIVE] Normal state
+livepatch: '$MOD_LIVEPATCH': starting patching transition
+livepatch: '$MOD_LIVEPATCH': completing patching transition
+$MOD_LIVEPATCH: post_patch_callback: vmlinux
+$MOD_LIVEPATCH: post_patch_callback: $MOD_TARGET_BUSY -> [MODULE_STATE_LIVE] Normal state
+livepatch: '$MOD_LIVEPATCH': patching complete
+% modprobe $MOD_TARGET
+livepatch: applying patch '$MOD_LIVEPATCH' to loading module '$MOD_TARGET'
+$MOD_LIVEPATCH: pre_patch_callback: $MOD_TARGET -> [MODULE_STATE_COMING] Full formed, running module_init
+$MOD_LIVEPATCH: post_patch_callback: $MOD_TARGET -> [MODULE_STATE_COMING] Full formed, running module_init
+$MOD_TARGET: ${MOD_TARGET}_init
+% rmmod $MOD_TARGET
+$MOD_TARGET: ${MOD_TARGET}_exit
+$MOD_LIVEPATCH: pre_unpatch_callback: $MOD_TARGET -> [MODULE_STATE_GOING] Going away
+livepatch: reverting patch '$MOD_LIVEPATCH' on unloading module '$MOD_TARGET'
+$MOD_LIVEPATCH: post_unpatch_callback: $MOD_TARGET -> [MODULE_STATE_GOING] Going away
+% echo 0 > /sys/kernel/livepatch/$MOD_LIVEPATCH/enabled
+livepatch: '$MOD_LIVEPATCH': initializing unpatching transition
+$MOD_LIVEPATCH: pre_unpatch_callback: vmlinux
+$MOD_LIVEPATCH: pre_unpatch_callback: $MOD_TARGET_BUSY -> [MODULE_STATE_LIVE] Normal state
+livepatch: '$MOD_LIVEPATCH': starting unpatching transition
+livepatch: '$MOD_LIVEPATCH': completing unpatching transition
+$MOD_LIVEPATCH: post_unpatch_callback: vmlinux
+$MOD_LIVEPATCH: post_unpatch_callback: $MOD_TARGET_BUSY -> [MODULE_STATE_LIVE] Normal state
+livepatch: '$MOD_LIVEPATCH': unpatching complete
+% rmmod $MOD_LIVEPATCH
+% rmmod $MOD_TARGET_BUSY
+$MOD_TARGET_BUSY: ${MOD_TARGET_BUSY}_exit"
+
+
+
+# TEST: busy target module
+#
+# A similar test as the previous one, but force the "busy" kernel module
+# to do longer work.
+#
+# The livepatching core will refuse to patch a task that is currently
+# executing a to-be-patched function -- the consistency model stalls the
+# current patch transition until this safety-check is met. Test a
+# scenario where one of a livepatch's target klp_objects sits on such a
+# function for a long time. Meanwhile, load and unload other target
+# kernel modules while the livepatch transition is in progress.
+#
+# - Load the "busy" kernel module, this time make it do 10 seconds worth
+# of work.
+#
+# - Meanwhile, the livepatch is loaded. Notice that the patch
+# transition does not complete as the targeted "busy" module is
+# sitting on a to-be-patched function.
+#
+# - Load a second target module (this one is an ordinary idle kernel
+# module). Note that *no* post-patch callbacks will be executed while
+# the livepatch is still in transition.
+#
+# - Request an unload of the simple kernel module. The patch is still
+# transitioning, so its pre-unpatch callbacks are skipped.
+#
+# - Finally the livepatch is disabled. Since none of the patch's
+# klp_object's post-patch callbacks executed, the remaining
+# klp_object's pre-unpatch callbacks are skipped.
+
+echo -n "TEST: busy target module ... "
+dmesg -C
+
+load_mod $MOD_TARGET_BUSY sleep_secs=10
+load_lp_nowait $MOD_LIVEPATCH
+# Don't wait for transition, load $MOD_TARGET while the transition
+# is still stalled in $MOD_TARGET_BUSY::busymod_work_func()
+sleep 5
+load_mod $MOD_TARGET
+unload_mod $MOD_TARGET
+disable_lp $MOD_LIVEPATCH
+unload_lp $MOD_LIVEPATCH
+unload_mod $MOD_TARGET_BUSY
+
+check_result "% modprobe $MOD_TARGET_BUSY sleep_secs=10
+$MOD_TARGET_BUSY: ${MOD_TARGET_BUSY}_init
+$MOD_TARGET_BUSY: busymod_work_func, sleeping 10 seconds ...
+% modprobe $MOD_LIVEPATCH
+livepatch: enabling patch '$MOD_LIVEPATCH'
+livepatch: '$MOD_LIVEPATCH': initializing patching transition
+$MOD_LIVEPATCH: pre_patch_callback: vmlinux
+$MOD_LIVEPATCH: pre_patch_callback: $MOD_TARGET_BUSY -> [MODULE_STATE_LIVE] Normal state
+livepatch: '$MOD_LIVEPATCH': starting patching transition
+% modprobe $MOD_TARGET
+livepatch: applying patch '$MOD_LIVEPATCH' to loading module '$MOD_TARGET'
+$MOD_LIVEPATCH: pre_patch_callback: $MOD_TARGET -> [MODULE_STATE_COMING] Full formed, running module_init
+$MOD_TARGET: ${MOD_TARGET}_init
+% rmmod $MOD_TARGET
+$MOD_TARGET: ${MOD_TARGET}_exit
+livepatch: reverting patch '$MOD_LIVEPATCH' on unloading module '$MOD_TARGET'
+$MOD_LIVEPATCH: post_unpatch_callback: $MOD_TARGET -> [MODULE_STATE_GOING] Going away
+% echo 0 > /sys/kernel/livepatch/$MOD_LIVEPATCH/enabled
+livepatch: '$MOD_LIVEPATCH': reversing transition from patching to unpatching
+livepatch: '$MOD_LIVEPATCH': starting unpatching transition
+livepatch: '$MOD_LIVEPATCH': completing unpatching transition
+$MOD_LIVEPATCH: post_unpatch_callback: vmlinux
+$MOD_LIVEPATCH: post_unpatch_callback: $MOD_TARGET_BUSY -> [MODULE_STATE_LIVE] Normal state
+livepatch: '$MOD_LIVEPATCH': unpatching complete
+% rmmod $MOD_LIVEPATCH
+% rmmod $MOD_TARGET_BUSY
+$MOD_TARGET_BUSY: busymod_work_func exit
+$MOD_TARGET_BUSY: ${MOD_TARGET_BUSY}_exit"
+
+
+# TEST: multiple livepatches
+#
+# Test loading multiple livepatches. This test-case is mainly for comparing
+# with the next test-case.
+#
+# - Load and unload two livepatches, pre and post (un)patch callbacks
+# execute as each patch progresses through its (un)patching
+# transition.
+
+echo -n "TEST: multiple livepatches ... "
+dmesg -C
+
+load_lp $MOD_LIVEPATCH
+load_lp $MOD_LIVEPATCH2
+disable_lp $MOD_LIVEPATCH2
+disable_lp $MOD_LIVEPATCH
+unload_lp $MOD_LIVEPATCH2
+unload_lp $MOD_LIVEPATCH
+
+check_result "% modprobe $MOD_LIVEPATCH
+livepatch: enabling patch '$MOD_LIVEPATCH'
+livepatch: '$MOD_LIVEPATCH': initializing patching transition
+$MOD_LIVEPATCH: pre_patch_callback: vmlinux
+livepatch: '$MOD_LIVEPATCH': starting patching transition
+livepatch: '$MOD_LIVEPATCH': completing patching transition
+$MOD_LIVEPATCH: post_patch_callback: vmlinux
+livepatch: '$MOD_LIVEPATCH': patching complete
+% modprobe $MOD_LIVEPATCH2
+livepatch: enabling patch '$MOD_LIVEPATCH2'
+livepatch: '$MOD_LIVEPATCH2': initializing patching transition
+$MOD_LIVEPATCH2: pre_patch_callback: vmlinux
+livepatch: '$MOD_LIVEPATCH2': starting patching transition
+livepatch: '$MOD_LIVEPATCH2': completing patching transition
+$MOD_LIVEPATCH2: post_patch_callback: vmlinux
+livepatch: '$MOD_LIVEPATCH2': patching complete
+% echo 0 > /sys/kernel/livepatch/$MOD_LIVEPATCH2/enabled
+livepatch: '$MOD_LIVEPATCH2': initializing unpatching transition
+$MOD_LIVEPATCH2: pre_unpatch_callback: vmlinux
+livepatch: '$MOD_LIVEPATCH2': starting unpatching transition
+livepatch: '$MOD_LIVEPATCH2': completing unpatching transition
+$MOD_LIVEPATCH2: post_unpatch_callback: vmlinux
+livepatch: '$MOD_LIVEPATCH2': unpatching complete
+% echo 0 > /sys/kernel/livepatch/$MOD_LIVEPATCH/enabled
+livepatch: '$MOD_LIVEPATCH': initializing unpatching transition
+$MOD_LIVEPATCH: pre_unpatch_callback: vmlinux
+livepatch: '$MOD_LIVEPATCH': starting unpatching transition
+livepatch: '$MOD_LIVEPATCH': completing unpatching transition
+$MOD_LIVEPATCH: post_unpatch_callback: vmlinux
+livepatch: '$MOD_LIVEPATCH': unpatching complete
+% rmmod $MOD_LIVEPATCH2
+% rmmod $MOD_LIVEPATCH"
+
+
+# TEST: atomic replace
+#
+# Load multiple livepatches, but the second as an 'atomic-replace'
+# patch. When the latter loads, the original livepatch should be
+# disabled and *none* of its pre/post-unpatch callbacks executed. On
+# the other hand, when the atomic-replace livepatch is disabled, its
+# pre/post-unpatch callbacks *should* be executed.
+#
+# - Load and unload two livepatches, the second of which has its
+# .replace flag set true.
+#
+# - Pre and post patch callbacks are executed for both livepatches.
+#
+# - Once the atomic replace module is loaded, only its pre and post
+# unpatch callbacks are executed.
+
+echo -n "TEST: atomic replace ... "
+dmesg -C
+
+load_lp $MOD_LIVEPATCH
+load_lp $MOD_LIVEPATCH2 replace=1
+disable_lp $MOD_LIVEPATCH2
+unload_lp $MOD_LIVEPATCH2
+unload_lp $MOD_LIVEPATCH
+
+check_result "% modprobe $MOD_LIVEPATCH
+livepatch: enabling patch '$MOD_LIVEPATCH'
+livepatch: '$MOD_LIVEPATCH': initializing patching transition
+$MOD_LIVEPATCH: pre_patch_callback: vmlinux
+livepatch: '$MOD_LIVEPATCH': starting patching transition
+livepatch: '$MOD_LIVEPATCH': completing patching transition
+$MOD_LIVEPATCH: post_patch_callback: vmlinux
+livepatch: '$MOD_LIVEPATCH': patching complete
+% modprobe $MOD_LIVEPATCH2 replace=1
+livepatch: enabling patch '$MOD_LIVEPATCH2'
+livepatch: '$MOD_LIVEPATCH2': initializing patching transition
+$MOD_LIVEPATCH2: pre_patch_callback: vmlinux
+livepatch: '$MOD_LIVEPATCH2': starting patching transition
+livepatch: '$MOD_LIVEPATCH2': completing patching transition
+$MOD_LIVEPATCH2: post_patch_callback: vmlinux
+livepatch: '$MOD_LIVEPATCH2': patching complete
+% echo 0 > /sys/kernel/livepatch/$MOD_LIVEPATCH2/enabled
+livepatch: '$MOD_LIVEPATCH2': initializing unpatching transition
+$MOD_LIVEPATCH2: pre_unpatch_callback: vmlinux
+livepatch: '$MOD_LIVEPATCH2': starting unpatching transition
+livepatch: '$MOD_LIVEPATCH2': completing unpatching transition
+$MOD_LIVEPATCH2: post_unpatch_callback: vmlinux
+livepatch: '$MOD_LIVEPATCH2': unpatching complete
+% rmmod $MOD_LIVEPATCH2
+% rmmod $MOD_LIVEPATCH"
+
+
+exit 0
--- /dev/null
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (C) 2018 Joe Lawrence <joe.lawrence@redhat.com>
+
+. $(dirname $0)/functions.sh
+
+MOD_LIVEPATCH=test_klp_livepatch
+MOD_REPLACE=test_klp_atomic_replace
+
+set_dynamic_debug
+
+
+# TEST: basic function patching
+# - load a livepatch that modifies the output from /proc/cmdline and
+# verify correct behavior
+# - unload the livepatch and make sure the patch was removed
+
+echo -n "TEST: basic function patching ... "
+dmesg -C
+
+load_lp $MOD_LIVEPATCH
+
+if [[ "$(cat /proc/cmdline)" != "$MOD_LIVEPATCH: this has been live patched" ]] ; then
+ echo -e "FAIL\n\n"
+ die "livepatch kselftest(s) failed"
+fi
+
+disable_lp $MOD_LIVEPATCH
+unload_lp $MOD_LIVEPATCH
+
+if [[ "$(cat /proc/cmdline)" == "$MOD_LIVEPATCH: this has been live patched" ]] ; then
+ echo -e "FAIL\n\n"
+ die "livepatch kselftest(s) failed"
+fi
+
+check_result "% modprobe $MOD_LIVEPATCH
+livepatch: enabling patch '$MOD_LIVEPATCH'
+livepatch: '$MOD_LIVEPATCH': initializing patching transition
+livepatch: '$MOD_LIVEPATCH': starting patching transition
+livepatch: '$MOD_LIVEPATCH': completing patching transition
+livepatch: '$MOD_LIVEPATCH': patching complete
+% echo 0 > /sys/kernel/livepatch/$MOD_LIVEPATCH/enabled
+livepatch: '$MOD_LIVEPATCH': initializing unpatching transition
+livepatch: '$MOD_LIVEPATCH': starting unpatching transition
+livepatch: '$MOD_LIVEPATCH': completing unpatching transition
+livepatch: '$MOD_LIVEPATCH': unpatching complete
+% rmmod $MOD_LIVEPATCH"
+
+
+# TEST: multiple livepatches
+# - load a livepatch that modifies the output from /proc/cmdline and
+# verify correct behavior
+# - load another livepatch and verify that both livepatches are active
+# - unload the second livepatch and verify that the first is still active
+# - unload the first livepatch and verify none are active
+
+echo -n "TEST: multiple livepatches ... "
+dmesg -C
+
+load_lp $MOD_LIVEPATCH
+
+grep 'live patched' /proc/cmdline > /dev/kmsg
+grep 'live patched' /proc/meminfo > /dev/kmsg
+
+load_lp $MOD_REPLACE replace=0
+
+grep 'live patched' /proc/cmdline > /dev/kmsg
+grep 'live patched' /proc/meminfo > /dev/kmsg
+
+disable_lp $MOD_REPLACE
+unload_lp $MOD_REPLACE
+
+grep 'live patched' /proc/cmdline > /dev/kmsg
+grep 'live patched' /proc/meminfo > /dev/kmsg
+
+disable_lp $MOD_LIVEPATCH
+unload_lp $MOD_LIVEPATCH
+
+grep 'live patched' /proc/cmdline > /dev/kmsg
+grep 'live patched' /proc/meminfo > /dev/kmsg
+
+check_result "% modprobe $MOD_LIVEPATCH
+livepatch: enabling patch '$MOD_LIVEPATCH'
+livepatch: '$MOD_LIVEPATCH': initializing patching transition
+livepatch: '$MOD_LIVEPATCH': starting patching transition
+livepatch: '$MOD_LIVEPATCH': completing patching transition
+livepatch: '$MOD_LIVEPATCH': patching complete
+$MOD_LIVEPATCH: this has been live patched
+% modprobe $MOD_REPLACE replace=0
+livepatch: enabling patch '$MOD_REPLACE'
+livepatch: '$MOD_REPLACE': initializing patching transition
+livepatch: '$MOD_REPLACE': starting patching transition
+livepatch: '$MOD_REPLACE': completing patching transition
+livepatch: '$MOD_REPLACE': patching complete
+$MOD_LIVEPATCH: this has been live patched
+$MOD_REPLACE: this has been live patched
+% echo 0 > /sys/kernel/livepatch/$MOD_REPLACE/enabled
+livepatch: '$MOD_REPLACE': initializing unpatching transition
+livepatch: '$MOD_REPLACE': starting unpatching transition
+livepatch: '$MOD_REPLACE': completing unpatching transition
+livepatch: '$MOD_REPLACE': unpatching complete
+% rmmod $MOD_REPLACE
+$MOD_LIVEPATCH: this has been live patched
+% echo 0 > /sys/kernel/livepatch/$MOD_LIVEPATCH/enabled
+livepatch: '$MOD_LIVEPATCH': initializing unpatching transition
+livepatch: '$MOD_LIVEPATCH': starting unpatching transition
+livepatch: '$MOD_LIVEPATCH': completing unpatching transition
+livepatch: '$MOD_LIVEPATCH': unpatching complete
+% rmmod $MOD_LIVEPATCH"
+
+
+# TEST: atomic replace livepatch
+# - load a livepatch that modifies the output from /proc/cmdline and
+# verify correct behavior
+# - load an atomic replace livepatch and verify that only the second is active
+# - remove the first livepatch and verify that the atomic replace livepatch
+# is still active
+# - remove the atomic replace livepatch and verify that none are active
+
+echo -n "TEST: atomic replace livepatch ... "
+dmesg -C
+
+load_lp $MOD_LIVEPATCH
+
+grep 'live patched' /proc/cmdline > /dev/kmsg
+grep 'live patched' /proc/meminfo > /dev/kmsg
+
+load_lp $MOD_REPLACE replace=1
+
+grep 'live patched' /proc/cmdline > /dev/kmsg
+grep 'live patched' /proc/meminfo > /dev/kmsg
+
+unload_lp $MOD_LIVEPATCH
+
+grep 'live patched' /proc/cmdline > /dev/kmsg
+grep 'live patched' /proc/meminfo > /dev/kmsg
+
+disable_lp $MOD_REPLACE
+unload_lp $MOD_REPLACE
+
+grep 'live patched' /proc/cmdline > /dev/kmsg
+grep 'live patched' /proc/meminfo > /dev/kmsg
+
+check_result "% modprobe $MOD_LIVEPATCH
+livepatch: enabling patch '$MOD_LIVEPATCH'
+livepatch: '$MOD_LIVEPATCH': initializing patching transition
+livepatch: '$MOD_LIVEPATCH': starting patching transition
+livepatch: '$MOD_LIVEPATCH': completing patching transition
+livepatch: '$MOD_LIVEPATCH': patching complete
+$MOD_LIVEPATCH: this has been live patched
+% modprobe $MOD_REPLACE replace=1
+livepatch: enabling patch '$MOD_REPLACE'
+livepatch: '$MOD_REPLACE': initializing patching transition
+livepatch: '$MOD_REPLACE': starting patching transition
+livepatch: '$MOD_REPLACE': completing patching transition
+livepatch: '$MOD_REPLACE': patching complete
+$MOD_REPLACE: this has been live patched
+% rmmod $MOD_LIVEPATCH
+$MOD_REPLACE: this has been live patched
+% echo 0 > /sys/kernel/livepatch/$MOD_REPLACE/enabled
+livepatch: '$MOD_REPLACE': initializing unpatching transition
+livepatch: '$MOD_REPLACE': starting unpatching transition
+livepatch: '$MOD_REPLACE': completing unpatching transition
+livepatch: '$MOD_REPLACE': unpatching complete
+% rmmod $MOD_REPLACE"
+
+
+exit 0
--- /dev/null
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (C) 2018 Joe Lawrence <joe.lawrence@redhat.com>
+
+. $(dirname $0)/functions.sh
+
+MOD_TEST=test_klp_shadow_vars
+
+set_dynamic_debug
+
+
+# TEST: basic shadow variable API
+# - load a module that exercises the shadow variable API
+
+echo -n "TEST: basic shadow variable API ... "
+dmesg -C
+
+load_mod $MOD_TEST
+unload_mod $MOD_TEST
+
+check_result "% modprobe $MOD_TEST
+$MOD_TEST: klp_shadow_get(obj=PTR5, id=0x1234) = PTR0
+$MOD_TEST: got expected NULL result
+$MOD_TEST: shadow_ctor: PTR6 -> PTR1
+$MOD_TEST: klp_shadow_alloc(obj=PTR5, id=0x1234, size=8, gfp_flags=GFP_KERNEL), ctor=PTR7, ctor_data=PTR1 = PTR6
+$MOD_TEST: shadow_ctor: PTR8 -> PTR2
+$MOD_TEST: klp_shadow_alloc(obj=PTR9, id=0x1234, size=8, gfp_flags=GFP_KERNEL), ctor=PTR7, ctor_data=PTR2 = PTR8
+$MOD_TEST: shadow_ctor: PTR10 -> PTR3
+$MOD_TEST: klp_shadow_alloc(obj=PTR5, id=0x1235, size=8, gfp_flags=GFP_KERNEL), ctor=PTR7, ctor_data=PTR3 = PTR10
+$MOD_TEST: klp_shadow_get(obj=PTR5, id=0x1234) = PTR6
+$MOD_TEST: got expected PTR6 -> PTR1 result
+$MOD_TEST: klp_shadow_get(obj=PTR9, id=0x1234) = PTR8
+$MOD_TEST: got expected PTR8 -> PTR2 result
+$MOD_TEST: klp_shadow_get(obj=PTR5, id=0x1235) = PTR10
+$MOD_TEST: got expected PTR10 -> PTR3 result
+$MOD_TEST: shadow_ctor: PTR11 -> PTR4
+$MOD_TEST: klp_shadow_get_or_alloc(obj=PTR12, id=0x1234, size=8, gfp_flags=GFP_KERNEL), ctor=PTR7, ctor_data=PTR4 = PTR11
+$MOD_TEST: klp_shadow_get_or_alloc(obj=PTR12, id=0x1234, size=8, gfp_flags=GFP_KERNEL), ctor=PTR7, ctor_data=PTR4 = PTR11
+$MOD_TEST: got expected PTR11 -> PTR4 result
+$MOD_TEST: shadow_dtor(obj=PTR5, shadow_data=PTR6)
+$MOD_TEST: klp_shadow_free(obj=PTR5, id=0x1234, dtor=PTR13)
+$MOD_TEST: klp_shadow_get(obj=PTR5, id=0x1234) = PTR0
+$MOD_TEST: got expected NULL result
+$MOD_TEST: shadow_dtor(obj=PTR9, shadow_data=PTR8)
+$MOD_TEST: klp_shadow_free(obj=PTR9, id=0x1234, dtor=PTR13)
+$MOD_TEST: klp_shadow_get(obj=PTR9, id=0x1234) = PTR0
+$MOD_TEST: got expected NULL result
+$MOD_TEST: shadow_dtor(obj=PTR12, shadow_data=PTR11)
+$MOD_TEST: klp_shadow_free(obj=PTR12, id=0x1234, dtor=PTR13)
+$MOD_TEST: klp_shadow_get(obj=PTR12, id=0x1234) = PTR0
+$MOD_TEST: got expected NULL result
+$MOD_TEST: klp_shadow_get(obj=PTR5, id=0x1235) = PTR10
+$MOD_TEST: got expected PTR10 -> PTR3 result
+$MOD_TEST: shadow_dtor(obj=PTR5, shadow_data=PTR10)
+$MOD_TEST: klp_shadow_free_all(id=0x1235, dtor=PTR13)
+$MOD_TEST: klp_shadow_get(obj=PTR5, id=0x1234) = PTR0
+$MOD_TEST: shadow_get() got expected NULL result
+% rmmod test_klp_shadow_vars"
+
+exit 0
git.samba.org / sfrench / cifs-2.6.git / commitdiff