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@ccrma.Stanford.EDU>
Acked-by: Pekka Enberg <penberg@kernel.org>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1311888176.2617.379.camel@laptop
Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/mm/slab.c b/mm/slab.c
index 0703578..6d90a09 100644 (file)
--- 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