2010-07-07 11:12:45 +00:00
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From: Miklos Szeredi <mszeredi@suse.cz>
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Subject: [PATCH 30/31] Fix use of uninitialized variable in cache_grow()
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Patch-mainline: not yet
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This fixes a bug in reserve-slub.patch.
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If cache_grow() was called with objp != NULL then the 'reserve' local
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variable wasn't initialized. This resulted in ac->reserve being set to
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a rubbish value. Due to this in some circumstances huge amounts of
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slab pages were allocated (due to slab_force_alloc() returning true),
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which caused atomic page allocation failures and slowdown of the
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system.
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Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
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Signed-off-by: Suresh Jayaraman <sjayaraman@suse.de>
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---
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mm/slab.c | 5 +++--
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1 file changed, 3 insertions(+), 2 deletions(-)
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--- a/mm/slab.c
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+++ b/mm/slab.c
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2011-04-19 20:09:59 +00:00
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@@ -2841,7 +2841,7 @@ static int cache_grow(struct kmem_cache
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2010-07-07 11:12:45 +00:00
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size_t offset;
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gfp_t local_flags;
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struct kmem_list3 *l3;
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- int reserve;
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+ int reserve = -1;
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/*
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* Be lazy and only check for valid flags here, keeping it out of the
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2011-04-19 20:09:59 +00:00
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@@ -2897,7 +2897,8 @@ static int cache_grow(struct kmem_cache
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2010-07-07 11:12:45 +00:00
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if (local_flags & __GFP_WAIT)
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local_irq_disable();
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check_irq_off();
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- slab_set_reserve(cachep, reserve);
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+ if (reserve != -1)
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+ slab_set_reserve(cachep, reserve);
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spin_lock(&l3->list_lock);
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/* Make slab active. */
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