[tip:core/urgent] slab, lockdep: Annotate the locks before using them

From: tip-bot for Peter Zijlstra
Date: Thu Aug 04 2011 - 04:36:41 EST


Commit-ID: 30765b92ada267c5395fc788623cb15233276f5c
Gitweb: http://git.kernel.org/tip/30765b92ada267c5395fc788623cb15233276f5c
Author: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
AuthorDate: Thu, 28 Jul 2011 23:22:56 +0200
Committer: Ingo Molnar <mingo@xxxxxxx>
CommitDate: Thu, 4 Aug 2011 10:18:00 +0200

slab, lockdep: Annotate the locks before using them

Fernando found we hit the regular OFF_SLAB 'recursion' before we
annotate the locks, cure this.

The relevant portion of the stack-trace:

> [ 0.000000] [<c085e24f>] rt_spin_lock+0x50/0x56
> [ 0.000000] [<c04fb406>] __cache_free+0x43/0xc3
> [ 0.000000] [<c04fb23f>] kmem_cache_free+0x6c/0xdc
> [ 0.000000] [<c04fb2fe>] slab_destroy+0x4f/0x53
> [ 0.000000] [<c04fb396>] free_block+0x94/0xc1
> [ 0.000000] [<c04fc551>] do_tune_cpucache+0x10b/0x2bb
> [ 0.000000] [<c04fc8dc>] enable_cpucache+0x7b/0xa7
> [ 0.000000] [<c0bd9d3c>] kmem_cache_init_late+0x1f/0x61
> [ 0.000000] [<c0bba687>] start_kernel+0x24c/0x363
> [ 0.000000] [<c0bba0ba>] i386_start_kernel+0xa9/0xaf

Reported-by: Fernando Lopez-Lezcano <nando@xxxxxxxxxxxxxxxxxx>
Acked-by: Pekka Enberg <penberg@xxxxxxxxxx>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Link: http://lkml.kernel.org/r/1311888176.2617.379.camel@laptop
Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
---
mm/slab.c | 6 +++---
1 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/mm/slab.c b/mm/slab.c
index 0703578..6d90a09 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -1666,6 +1666,9 @@ void __init kmem_cache_init_late(void)
{
struct kmem_cache *cachep;

+ /* Annotate slab for lockdep -- annotate the malloc caches */
+ init_lock_keys();
+
/* 6) resize the head arrays to their final sizes */
mutex_lock(&cache_chain_mutex);
list_for_each_entry(cachep, &cache_chain, next)
@@ -1676,9 +1679,6 @@ void __init kmem_cache_init_late(void)
/* Done! */
g_cpucache_up = FULL;

- /* Annotate slab for lockdep -- annotate the malloc caches */
- init_lock_keys();
-
/*
* Register a cpu startup notifier callback that initializes
* cpu_cache_get for all new cpus
--
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