src/patches/suse-2.6.27.31/patches.suse/SoN-fix-uninitialized-variable.patch

   1 From: Miklos Szeredi <mszeredi@suse.cz>
   2 Subject: Fix use of uninitialized variable in cache_grow()
   3 Patch-mainline: no
   4 References: bnc#444597
   5
   6 This fixes a bug in SoN-08-reserve-slub.patch.
   7
   8 If cache_grow() was called with objp != NULL then the 'reserve' local
   9 variable wasn't initialized. This resulted in ac->reserve being set to
  10 a rubbish value.  Due to this in some circumstances huge amounts of
  11 slab pages were allocated (due to slab_force_alloc() returning true),
  12 which caused atomic page allocation failures and slowdown of the
  13 system.
  14
  15 Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
  16 ---
  17  mm/slab.c |    5 +++--
  18  1 file changed, 3 insertions(+), 2 deletions(-)
  19
  20 Index: linux-2.6.27/mm/slab.c
  21 ===================================================================
  22 --- linux-2.6.27.orig/mm/slab.c 2008-12-03 22:11:12.000000000 +0100
  23 +++ linux-2.6.27/mm/slab.c      2008-12-03 22:14:37.000000000 +0100
  24 @@ -2785,7 +2785,7 @@ static int cache_grow(struct kmem_cache
  25         size_t offset;
  26         gfp_t local_flags;
  27         struct kmem_list3 *l3;
  28 -       int reserve;
  29 +       int reserve = -1;
  30
  31         /*
  32          * Be lazy and only check for valid flags here,  keeping it out of the
  33 @@ -2841,7 +2841,8 @@ static int cache_grow(struct kmem_cache
  34         if (local_flags & __GFP_WAIT)
  35                 local_irq_disable();
  36         check_irq_off();
  37 -       slab_set_reserve(cachep, reserve);
  38 +       if (reserve != -1)
  39 +               slab_set_reserve(cachep, reserve);
  40         spin_lock(&l3->list_lock);
  41
  42         /* Make slab active. */