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author | Catalin Marinas <catalin.marinas@arm.com> | 2015-06-24 16:58:29 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2015-06-24 17:49:45 -0700 |
commit | e781a9ab4847a81224667f5faab0b2bc5f78908f (patch) | |
tree | 7a2511fbb4403f68cac254858b2a8275b837a468 /mm/oom_kill.c | |
parent | c5f3b1a51a591c18c8b33983908e7fdda6ae417e (diff) |
mm: kmemleak: fix delete_object_*() race when called on the same memory block
Calling delete_object_*() on the same pointer is not a standard use case
(unless there is a bug in the code calling kmemleak_free()). However,
during kmemleak disabling (error or user triggered via /sys), there is a
potential race between kmemleak_free() calls on a CPU and
__kmemleak_do_cleanup() on a different CPU.
The current delete_object_*() implementation first performs a look-up
holding kmemleak_lock, increments the object->use_count and then
re-acquires kmemleak_lock to remove the object from object_tree_root and
object_list.
This patch simplifies the delete_object_*() mechanism to both look up
and remove an object from the object_tree_root and object_list
atomically (guarded by kmemleak_lock). This allows safe concurrent
calls to delete_object_*() on the same pointer without additional
locking for synchronising the kmemleak_free_enabled flag.
A side effect is a slight improvement in the delete_object_*() performance
by avoiding acquiring kmemleak_lock twice and incrementing/decrementing
object->use_count.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/oom_kill.c')
0 files changed, 0 insertions, 0 deletions