init: fix false positives in W+X checking

[sfrench/cifs-2.6.git] / kernel / module.c

diff --git a/kernel/module.c b/kernel/module.c
index ce8066b881782f9db47c7fc85d8659e1b9cfe9ac..c9bea7f2b43e3b2568f2adeaa299a6545df41df8 100644 (file)
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -3517,6 +3517,11 @@ static noinline int do_init_module(struct module *mod)
         * walking this with preempt disabled.  In all the failure paths, we
         * call synchronize_sched(), but we don't want to slow down the success
         * path, so use actual RCU here.
+        * Note that module_alloc() on most architectures creates W+X page
+        * mappings which won't be cleaned up until do_free_init() runs.  Any
+        * code such as mark_rodata_ro() which depends on those mappings to
+        * be cleaned up needs to sync with the queued work - ie
+        * rcu_barrier_sched()
         */
        call_rcu_sched(&freeinit->rcu, do_free_init);
        mutex_unlock(&module_mutex);