The patch titled
Subject: debugobjects: make kmemleak ignore debug objects
has been added to the -mm tree. Its filename is
debugobjects-make-kmemleak-ignore-debug-objects.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/debugobjects-make-kmemleak-ignore-debug-objects.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/debugobjects-make-kmemleak-ignore-debug-objects.patch
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------------------------------------------------------
From: Waiman Long <longman@xxxxxxxxxx>
Subject: debugobjects: make kmemleak ignore debug objects
The allocated debug objects are either on the free list or in the hashed
bucket lists. So they won't get lost. However if both debug objects and
kmemleak are enabled and kmemleak scanning is done while some of the debug
objects are transitioning from one list to the others, false negative
reporting of memory leaks may happen for those objects. For example,
[38687.275678] kmemleak: 12 new suspected memory leaks (see
/sys/kernel/debug/kmemleak)
unreferenced object 0xffff92e98aabeb68 (size 40):
comm "ksmtuned", pid 4344, jiffies 4298403600 (age 906.430s)
hex dump (first 32 bytes):
00 00 00 00 00 00 00 00 d0 bc db 92 e9 92 ff ff ................
01 00 00 00 00 00 00 00 38 36 8a 61 e9 92 ff ff ........86.a....
backtrace:
[<ffffffff8fa5378a>] kmemleak_alloc+0x4a/0xa0
[<ffffffff8f47c019>] kmem_cache_alloc+0xe9/0x320
[<ffffffff8f62ed96>] __debug_object_init+0x3e6/0x400
[<ffffffff8f62ef01>] debug_object_activate+0x131/0x210
[<ffffffff8f330d9f>] __call_rcu+0x3f/0x400
[<ffffffff8f33117d>] call_rcu_sched+0x1d/0x20
[<ffffffff8f4a183c>] put_object+0x2c/0x40
[<ffffffff8f4a188c>] __delete_object+0x3c/0x50
[<ffffffff8f4a18bd>] delete_object_full+0x1d/0x20
[<ffffffff8fa535c2>] kmemleak_free+0x32/0x80
[<ffffffff8f47af07>] kmem_cache_free+0x77/0x350
[<ffffffff8f453912>] unlink_anon_vmas+0x82/0x1e0
[<ffffffff8f440341>] free_pgtables+0xa1/0x110
[<ffffffff8f44af91>] exit_mmap+0xc1/0x170
[<ffffffff8f29db60>] mmput+0x80/0x150
[<ffffffff8f2a7609>] do_exit+0x2a9/0xd20
The references in the debug objects may also hide a real memory leak.
As there is no point in having kmemleak to track debug object allocations,
kmemleak checking is now disabled for debug objects.
Link: http://lkml.kernel.org/r/1502718733-8527-1-git-send-email-longman@xxxxxxxxxx
Signed-off-by: Waiman Long <longman@xxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
init/main.c | 2 +-
lib/debugobjects.c | 3 +++
2 files changed, 4 insertions(+), 1 deletion(-)
diff -puN init/main.c~debugobjects-make-kmemleak-ignore-debug-objects init/main.c
--- a/init/main.c~debugobjects-make-kmemleak-ignore-debug-objects
+++ a/init/main.c
@@ -658,8 +658,8 @@ asmlinkage __visible void __init start_k
initrd_start = 0;
}
#endif
- debug_objects_mem_init();
kmemleak_init();
+ debug_objects_mem_init();
setup_per_cpu_pageset();
numa_policy_init();
if (late_time_init)
diff -puN lib/debugobjects.c~debugobjects-make-kmemleak-ignore-debug-objects lib/debugobjects.c
--- a/lib/debugobjects.c~debugobjects-make-kmemleak-ignore-debug-objects
+++ a/lib/debugobjects.c
@@ -18,6 +18,7 @@
#include <linux/debugfs.h>
#include <linux/slab.h>
#include <linux/hash.h>
+#include <linux/kmemleak.h>
#define ODEBUG_HASH_BITS 14
#define ODEBUG_HASH_SIZE (1 << ODEBUG_HASH_BITS)
@@ -110,6 +111,7 @@ static void fill_pool(void)
if (!new)
return;
+ kmemleak_ignore(new);
raw_spin_lock_irqsave(&pool_lock, flags);
hlist_add_head(&new->node, &obj_pool);
debug_objects_allocated++;
@@ -1080,6 +1082,7 @@ static int __init debug_objects_replace_
obj = kmem_cache_zalloc(obj_cache, GFP_KERNEL);
if (!obj)
goto free;
+ kmemleak_ignore(obj);
hlist_add_head(&obj->node, &objects);
}
_
Patches currently in -mm which might be from longman@xxxxxxxxxx are
debugobjects-make-kmemleak-ignore-debug-objects.patch
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