Messages in this thread Patch in this message | | | Date | Tue, 28 Jul 2009 16:40:34 -0700 | From | Greg KH <> | Subject | [patch 05/71] fix RCU-callback-after-kmem_cache_destroy problem in sl[aou]b |
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2.6.30-stable review patch. If anyone has any objections, please let us know.
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From: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
commit 7ed9f7e5db58c6e8c2b4b738a75d5dcd8e17aad5 upstream.
Jesper noted that kmem_cache_destroy() invokes synchronize_rcu() rather than rcu_barrier() in the SLAB_DESTROY_BY_RCU case, which could result in RCU callbacks accessing a kmem_cache after it had been destroyed.
Acked-by: Matt Mackall <mpm@selenic.com> Reported-by: Jesper Dangaard Brouer <hawk@comx.dk> Signed-off-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>
--- mm/slab.c | 2 +- mm/slob.c | 2 ++ mm/slub.c | 2 ++ 3 files changed, 5 insertions(+), 1 deletion(-)
--- a/mm/slab.c +++ b/mm/slab.c @@ -2592,7 +2592,7 @@ void kmem_cache_destroy(struct kmem_cach } if (unlikely(cachep->flags & SLAB_DESTROY_BY_RCU)) - synchronize_rcu(); + rcu_barrier(); __kmem_cache_destroy(cachep); mutex_unlock(&cache_chain_mutex); --- a/mm/slob.c +++ b/mm/slob.c @@ -590,6 +590,8 @@ EXPORT_SYMBOL(kmem_cache_create); void kmem_cache_destroy(struct kmem_cache *c) { + if (c->flags & SLAB_DESTROY_BY_RCU) + rcu_barrier(); slob_free(c, sizeof(struct kmem_cache)); } EXPORT_SYMBOL(kmem_cache_destroy); --- a/mm/slub.c +++ b/mm/slub.c @@ -2490,6 +2490,8 @@ static inline int kmem_cache_close(struc */ 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) {
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