| From 7ed9f7e5db58c6e8c2b4b738a75d5dcd8e17aad5 Mon Sep 17 00:00:00 2001 |
| From: Paul E. McKenney <paulmck@linux.vnet.ibm.com> |
| Date: Thu, 25 Jun 2009 12:31:37 -0700 |
| Subject: fix RCU-callback-after-kmem_cache_destroy problem in sl[aou]b |
| |
| 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) { |
