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authorEric Dumazet <eric.dumazet@gmail.com>2009-09-03 22:38:59 +0300
committerGreg Kroah-Hartman <gregkh@suse.de>2009-09-15 10:37:24 -0700
commit82b257c06a952cbda39a26012fd7e7978ac0b423 (patch)
tree9225676bcf3eaa6d7a15ce70fc312bcfae576b8f
parent9579d79f10d42ce275c94b945a3df2f5173d8041 (diff)
slub: Fix kmem_cache_destroy() with SLAB_DESTROY_BY_RCU
commit d76b1590e06a63a3d8697168cd0aabf1c4b3cb3a upstream. kmem_cache_destroy() should call rcu_barrier() *after* kmem_cache_close() and *before* sysfs_slab_remove() or risk rcu_free_slab() being called after kmem_cache is deleted (kfreed). rmmod nf_conntrack can crash the machine because it has to kmem_cache_destroy() a SLAB_DESTROY_BY_RCU enabled cache. Reported-by: Zdenek Kabelac <zdenek.kabelac@gmail.com> Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
-rw-r--r--mm/slub.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/mm/slub.c b/mm/slub.c
index f0175b454c74..cbf856b5bc08 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -2447,8 +2447,6 @@ static inline int kmem_cache_close(struct kmem_cache *s)
*/
void kmem_cache_destroy(struct kmem_cache *s)
{
- if (s->flags & SLAB_DESTROY_BY_RCU)
- rcu_barrier();
down_write(&slub_lock);
s->refcount--;
if (!s->refcount) {
@@ -2459,6 +2457,8 @@ void kmem_cache_destroy(struct kmem_cache *s)
"still has objects.\n", s->name, __func__);
dump_stack();
}
+ if (s->flags & SLAB_DESTROY_BY_RCU)
+ rcu_barrier();
sysfs_slab_remove(s);
} else
up_write(&slub_lock);