Messages in this thread Patch in this message | | | From | Suresh Jayaraman <> | Subject | [PATCH 30/31] Fix use of uninitialized variable in cache_grow() | Date | Thu, 1 Oct 2009 19:40:57 +0530 |
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From: Miklos Szeredi <mszeredi@suse.cz>
This fixes a bug in reserve-slub.patch.
If cache_grow() was called with objp != NULL then the 'reserve' local variable wasn't initialized. This resulted in ac->reserve being set to a rubbish value. Due to this in some circumstances huge amounts of slab pages were allocated (due to slab_force_alloc() returning true), which caused atomic page allocation failures and slowdown of the system.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Signed-off-by: Suresh Jayaraman <sjayaraman@suse.de> --- mm/slab.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)
Index: mmotm/mm/slab.c =================================================================== --- mmotm.orig/mm/slab.c +++ mmotm/mm/slab.c @@ -2760,7 +2760,7 @@ static int cache_grow(struct kmem_cache size_t offset; gfp_t local_flags; struct kmem_list3 *l3; - int reserve; + int reserve = -1; /* * Be lazy and only check for valid flags here, keeping it out of the @@ -2816,7 +2816,8 @@ static int cache_grow(struct kmem_cache if (local_flags & __GFP_WAIT) local_irq_disable(); check_irq_off(); - slab_set_reserve(cachep, reserve); + if (reserve != -1) + slab_set_reserve(cachep, reserve); spin_lock(&l3->list_lock); /* Make slab active. */
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