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authorPekka Enberg <penberg@cs.helsinki.fi>2007-05-06 14:49:03 -0700
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-05-07 12:12:51 -0700
commit714b8171af9c930a59a0da8f6fe50518e70ab035 (patch)
treeb63f21c4efd165637c938267d7e542df18d93c99
parent5f22df00a009e3f86301366c0ecddb63ebd22af9 (diff)
slab: ensure cache_alloc_refill terminates
If slab->inuse is corrupted, cache_alloc_refill can enter an infinite loop as detailed by Michael Richardson in the following post: <http://lkml.org/lkml/2007/2/16/292>. This adds a BUG_ON to catch those cases. Cc: Michael Richardson <mcr@sandelman.ca> Acked-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--mm/slab.c8
1 files changed, 8 insertions, 0 deletions
diff --git a/mm/slab.c b/mm/slab.c
index 8b71a9c3daa..21b2aef2525 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -2990,6 +2990,14 @@ retry:
slabp = list_entry(entry, struct slab, list);
check_slabp(cachep, slabp);
check_spinlock_acquired(cachep);
+
+ /*
+ * The slab was either on partial or free list so
+ * there must be at least one object available for
+ * allocation.
+ */
+ BUG_ON(slabp->inuse < 0 || slabp->inuse >= cachep->num);
+
while (slabp->inuse < cachep->num && batchcount--) {
STATS_INC_ALLOCED(cachep);
STATS_INC_ACTIVE(cachep);