kmemleak:

From: Sergey Senozhatsky
Date: Thu May 31 2012 - 07:56:17 EST


Hello,

I'm seeing pretty often (may be 10-15 times during last 2 months) kmemleak failed
allocation:

[ 8213.936237] kmemleak: Kernel memory leak detector disabled
[ 8214.660454] kmemleak: Automatic memory scanning thread ended


I've a patch that gives a bit more info on last kmemleak step (for example):

[ 8213.935927] kmemleak: Cannot allocate a kmemleak_object structure
[ 8213.935950] kmemleak: size: 192, mask: 70144
[ 8213.935955] Pid: 444, comm: kswapd0 Not tainted 3.5.0-rc0-dbg-10118-gaf992ce-dirty #1152
[ 8213.935957] Call Trace:
[ 8213.935986] [<ffffffff8111ec4c>] create_object+0x7d/0x305
[ 8213.936009] [<ffffffff810dc89e>] ? mempool_alloc_slab+0x15/0x17
[ 8213.936014] [<ffffffff810dc89e>] ? mempool_alloc_slab+0x15/0x17
[ 8213.936020] [<ffffffff8149a2e3>] kmemleak_alloc+0x26/0x43
[ 8213.936041] [<ffffffff81114d54>] kmem_cache_alloc+0xd7/0x1e6
[ 8213.936046] [<ffffffff810dc89e>] mempool_alloc_slab+0x15/0x17
[ 8213.936050] [<ffffffff810dcb28>] mempool_alloc+0x81/0x146
[ 8213.936074] [<ffffffff81284052>] ? do_raw_spin_lock+0x69/0xe9
[ 8213.936079] [<ffffffff81150829>] bio_alloc_bioset+0x33/0xc4
[ 8213.936085] [<ffffffff8110a0f9>] ? get_swap_bio+0x79/0x79
[ 8213.936089] [<ffffffff811508cf>] bio_alloc+0x15/0x24
[ 8213.936109] [<ffffffff8110a09f>] get_swap_bio+0x1f/0x79
[ 8213.936114] [<ffffffff8110a20b>] swap_writepage+0x3d/0x9f
[ 8213.936120] [<ffffffff810e8cde>] pageout.isra.48+0x127/0x2f9
[ 8213.936141] [<ffffffff810ea570>] shrink_inactive_list+0x4eb/0x94f
[ 8213.936146] [<ffffffff810ead10>] shrink_lruvec+0x33c/0x46f
[ 8213.936151] [<ffffffff810ebb94>] kswapd+0x680/0xa58
[ 8213.936172] [<ffffffff810eb514>] ? try_to_free_pages+0x27f/0x27f
[ 8213.936178] [<ffffffff81053da5>] kthread+0x8b/0x93
[ 8213.936184] [<ffffffff814be134>] kernel_thread_helper+0x4/0x10
[ 8213.936207] [<ffffffff814b59f0>] ? retint_restore_args+0x13/0x13
[ 8213.936211] [<ffffffff81053d1a>] ? __init_kthread_worker+0x5a/0x5a
[ 8213.936215] [<ffffffff814be130>] ? gs_change+0x13/0x13

The question is - could it be of any use to printk stack trace with function parameters
(size, flag) for failed allocation?

If so, I'll prepare a proper patch.



Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@xxxxxxxxx>

---

mm/kmemleak.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/mm/kmemleak.c b/mm/kmemleak.c
index 45eb621..60c49a5 100644
--- a/mm/kmemleak.c
+++ b/mm/kmemleak.c
@@ -521,8 +521,10 @@ static struct kmemleak_object *create_object(unsigned long ptr, size_t size,

object = kmem_cache_alloc(object_cache, gfp_kmemleak_mask(gfp));
if (!object) {
+ write_lock_irqsave(&kmemleak_lock, flags);
pr_warning("Cannot allocate a kmemleak_object structure\n");
- kmemleak_disable();
+ kmemleak_stop("size: %zu, mask: %u\n", size, gfp_kmemleak_mask(gfp));
+ write_unlock_irqrestore(&kmemleak_lock, flags);
return NULL;
}

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