mm: Make mem_dump_obj() handle vmalloc() memory

This commit adds vmalloc() support to mem_dump_obj().  Note that the
vmalloc_dump_obj() function combines the checking and dumping, in
contrast with the split between kmem_valid_obj() and kmem_dump_obj().
The reason for the difference is that the checking in the vmalloc()
case involves acquiring a global lock, and redundant acquisitions of
global locks should be avoided, even on not-so-fast paths.

Note that this change causes on-stack variables to be reported as
vmalloc() storage from kernel_clone() or similar, depending on the degree
of inlining that your compiler does.  This is likely more helpful than
the earlier "non-paged (local) memory".

Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: <linux-mm@kvack.org>
Reported-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Tested-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

diff --git a/include/linux/vmalloc.h b/include/linux/vmalloc.h
index 80c0181c411dff2a2f165d8e26e774841f80f9a6..c18f4751a704ab6985ef63f5b27cceb3422eb6ed 100644 (file)
--- a/include/linux/vmalloc.h
+++ b/include/linux/vmalloc.h
@@ -246,4 +246,10 @@ pcpu_free_vm_areas(struct vm_struct **vms, int nr_vms)
 int register_vmap_purge_notifier(struct notifier_block *nb);
 int unregister_vmap_purge_notifier(struct notifier_block *nb);
 
+#ifdef CONFIG_MMU
+bool vmalloc_dump_obj(void *object);
+#else
+static inline bool vmalloc_dump_obj(void *object) { return false; }
+#endif
+
 #endif /* _LINUX_VMALLOC_H */

diff --git a/mm/util.c b/mm/util.c
index 92f23d2c127701f54dabd48972de29b4451fbc46..54870226cea64aa36e253b1c1f196e9c8ec58c2a 100644 (file)
--- a/mm/util.c
+++ b/mm/util.c
@@ -996,18 +996,20 @@ int __weak memcmp_pages(struct page *page1, struct page *page2)
  */
 void mem_dump_obj(void *object)
 {
+       if (kmem_valid_obj(object)) {
+               kmem_dump_obj(object);
+               return;
+       }
+       if (vmalloc_dump_obj(object))
+               return;
        if (!virt_addr_valid(object)) {
                if (object == NULL)
                        pr_cont(" NULL pointer.\n");
                else if (object == ZERO_SIZE_PTR)
                        pr_cont(" zero-size pointer.\n");
                else
-                       pr_cont(" non-paged (local) memory.\n");
-               return;
-       }
-       if (kmem_valid_obj(object)) {
-               kmem_dump_obj(object);
+                       pr_cont(" non-paged memory.\n");
                return;
        }
-       pr_cont(" non-slab memory.\n");
+       pr_cont(" non-slab/vmalloc memory.\n");
 }

diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 4d88fe5a277ac2d0e520f37f4dc7ec0a779fc9fe..c274ea4f14ea326d1279d448a15055df6613168b 100644 (file)
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -3448,6 +3448,18 @@ void pcpu_free_vm_areas(struct vm_struct **vms, int nr_vms)
 }
 #endif /* CONFIG_SMP */
 
+bool vmalloc_dump_obj(void *object)
+{
+       struct vm_struct *vm;
+       void *objp = (void *)PAGE_ALIGN((unsigned long)object);
+
+       vm = find_vm_area(objp);
+       if (!vm)
+               return false;
+       pr_cont(" vmalloc allocated at %pS\n", vm->caller);
+       return true;
+}
+
 #ifdef CONFIG_PROC_FS
 static void *s_start(struct seq_file *m, loff_t *pos)
        __acquires(&vmap_purge_lock)