Some drivers would like to record stacktraces in order to aide leak
tracing. As stackdepot already provides a facility for only storing the
unique traces, thereby reducing the memory required, export that
functionality for use by drivers.
The code was originally created for KASAN and moved under lib in commit
cd11016e5f521 ("mm, kasan: stackdepot implementation. Enable stackdepot
for SLAB") so that it could be shared with mm/. In turn, we want to
share it now with drivers.
Link: http://lkml.kernel.org/r/20161108133209.22704-1-chris@chris-wilson.co.uk
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Bug: 64145065
(cherry-picked from ae65a21fb851f09bf6341761d884fb86b644b75a)
Change-Id: I3bf7ab5c6526c1ac895ac98d2d37cc26ea05bbde
Signed-off-by: Paul Lawrence <paullawrence@google.com>
KASAN uses stackdepot to memorize stacks for all kmalloc/kfree calls.
Current stackdepot capacity is 16MB (1024 top level entries x 4 pages on
second level). Size of each stack is (num_frames + 3) * sizeof(long).
Which gives us ~84K stacks. This capacity was chosen empirically and it
is enough to run kernel normally.
However, when lots of configs are enabled and a fuzzer tries to maximize
code coverage, it easily hits the limit within tens of minutes. I've
tested for long a time with number of top level entries bumped 4x
(4096). And I think I've seen overflow only once. But I don't have all
configs enabled and code coverage has not reached maximum yet. So bump
it 8x to 8192.
Since we have two-level table, memory cost of this is very moderate --
currently the top-level table is 8KB, with this patch it is 64KB, which
is negligible under KASAN.
Here is some approx math.
128MB allows us to memorize ~670K stacks (assuming stack is ~200b).
I've grepped kernel for kmalloc|kfree|kmem_cache_alloc|kmem_cache_free|
kzalloc|kstrdup|kstrndup|kmemdup and it gives ~60K matches. Most of
alloc/free call sites are reachable with only one stack. But some
utility functions can have large fanout. Assuming average fanout is 5x,
total number of alloc/free stacks is ~300K.
Link: http://lkml.kernel.org/r/1476458416-122131-1-git-send-email-dvyukov@google.com
Signed-off-by: Dmitry Vyukov <dvyukov@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Baozeng Ding <sploving1@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Bug: 64145065
(cherry-picked from 02754e0a484a50a92d44c38879f2cb2792ebc572)
Change-Id: Ia08e608741a7e6dda059f0d6aa30dfdf8f52ef25
Signed-off-by: Paul Lawrence <paullawrence@google.com>
This (large, atomic) allocation attempt can fail. We expect and handle
that, so avoid the scary warning.
Link: http://lkml.kernel.org/r/20160720151905.GB19146@node.shutemov.name
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Rik van Riel <riel@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Bug: 64145065
(cherry-picked from 87cc271d5e4320d705cfdf59f68d4d037b3511b2)
Change-Id: I1b20189c6c83287ac64f408804dc0b3c29789323
Signed-off-by: Paul Lawrence <paullawrence@google.com>
Recently, we allow to save the stacktrace whose hashed value is 0. It
causes the problem that stackdepot could return 0 even if in success.
User of stackdepot cannot distinguish whether it is success or not so we
need to solve this problem. In this patch, 1 bit are added to handle
and make valid handle none 0 by setting this bit. After that, valid
handle will not be 0 and 0 handle will represent failure correctly.
Fixes: 33334e25769c ("lib/stackdepot.c: allow the stack trace hash to be zero")
Link: http://lkml.kernel.org/r/1462252403-1106-1-git-send-email-iamjoonsoo.kim@lge.com
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Bug: 64145065
(cherry-picked from 7c31190bcfdbff225950902a9f226e4eb79ca94f)
Change-Id: Ibfb0eb8439225e03e72ed714570d8efac47188a0
Signed-off-by: Paul Lawrence <paullawrence@google.com>
Do not bail out from depot_save_stack() if the stack trace has zero hash.
Initially depot_save_stack() silently dropped stack traces with zero
hashes, however there's actually no point in reserving this zero value.
Reported-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Alexander Potapenko <glider@google.com>
Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Bug: 64145065
(cherry-picked from 33334e25769c6ad69b983379578f42581d99a2f9)
Change-Id: I44c9c5a881e2f4176c3946905b8f11b26f45bc00
Signed-off-by: Paul Lawrence <paullawrence@google.com>
Implement the stack depot and provide CONFIG_STACKDEPOT. Stack depot
will allow KASAN store allocation/deallocation stack traces for memory
chunks. The stack traces are stored in a hash table and referenced by
handles which reside in the kasan_alloc_meta and kasan_free_meta
structures in the allocated memory chunks.
IRQ stack traces are cut below the IRQ entry point to avoid unnecessary
duplication.
Right now stackdepot support is only enabled in SLAB allocator. Once
KASAN features in SLAB are on par with those in SLUB we can switch SLUB
to stackdepot as well, thus removing the dependency on SLUB stack
bookkeeping, which wastes a lot of memory.
This patch is based on the "mm: kasan: stack depots" patch originally
prepared by Dmitry Chernenkov.
Joonsoo has said that he plans to reuse the stackdepot code for the
mm/page_owner.c debugging facility.
[akpm@linux-foundation.org: s/depot_stack_handle/depot_stack_handle_t]
[aryabinin@virtuozzo.com: comment style fixes]
Signed-off-by: Alexander Potapenko <glider@google.com>
Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Andrey Konovalov <adech.fo@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Konstantin Serebryany <kcc@google.com>
Cc: Dmitry Chernenkov <dmitryc@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Bug: 64145065
(cherry-picked from cd11016e5f5212c13c0cec7384a525edc93b4921)
Change-Id: Ic804318410823b95d84e264a6334e018f21ef943
Signed-off-by: Paul Lawrence <paullawrence@google.com>
