projects / ipfire-2.x.git / blame
| Commit | Line | Data |
|---|---|---|
| 2cb7cef9 BS |
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. */ |