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authorDmitry Safonov <dsafonov@virtuozzo.com>2016-02-17 13:11:37 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2016-02-18 16:23:24 -0800
commit52b4b950b50740bff507a62907e86710743c22e7 (patch)
tree16ec207435a99a4bc95482906acd8468fd322b82 /mm/slab.c
parent1ac0b6dec656f3f78d1c3dd216fad84cb4d0a01e (diff)
mm: slab: free kmem_cache_node after destroy sysfs file
When slub_debug alloc_calls_show is enabled we will try to track location and user of slab object on each online node, kmem_cache_node structure and cpu_cache/cpu_slub shouldn't be freed till there is the last reference to sysfs file. This fixes the following panic: BUG: unable to handle kernel NULL pointer dereference at 0000000000000020 IP: list_locations+0x169/0x4e0 PGD 257304067 PUD 438456067 PMD 0 Oops: 0000 [#1] SMP CPU: 3 PID: 973074 Comm: cat ve: 0 Not tainted 3.10.0-229.7.2.ovz.9.30-00007-japdoll-dirty #2 9.30 Hardware name: DEPO Computers To Be Filled By O.E.M./H67DE3, BIOS L1.60c 07/14/2011 task: ffff88042a5dc5b0 ti: ffff88037f8d8000 task.ti: ffff88037f8d8000 RIP: list_locations+0x169/0x4e0 Call Trace: alloc_calls_show+0x1d/0x30 slab_attr_show+0x1b/0x30 sysfs_read_file+0x9a/0x1a0 vfs_read+0x9c/0x170 SyS_read+0x58/0xb0 system_call_fastpath+0x16/0x1b Code: 5e 07 12 00 b9 00 04 00 00 3d 00 04 00 00 0f 4f c1 3d 00 04 00 00 89 45 b0 0f 84 c3 00 00 00 48 63 45 b0 49 8b 9c c4 f8 00 00 00 <48> 8b 43 20 48 85 c0 74 b6 48 89 df e8 46 37 44 00 48 8b 53 10 CR2: 0000000000000020 Separated __kmem_cache_release from __kmem_cache_shutdown which now called on slab_kmem_cache_release (after the last reference to sysfs file object has dropped). Reintroduced locking in free_partial as sysfs file might access cache's partial list after shutdowning - partial revert of the commit 69cb8e6b7c29 ("slub: free slabs without holding locks"). Zap __remove_partial and use remove_partial (w/o underscores) as free_partial now takes list_lock which s partial revert for commit 1e4dd9461fab ("slub: do not assert not having lock in removing freed partial") Signed-off-by: Dmitry Safonov <dsafonov@virtuozzo.com> Suggested-by: Vladimir Davydov <vdavydov@virtuozzo.com> Acked-by: Vladimir Davydov <vdavydov@virtuozzo.com> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/slab.c')
-rw-r--r--mm/slab.c12
1 files changed, 6 insertions, 6 deletions
diff --git a/mm/slab.c b/mm/slab.c
index 6ecc697a8bc4..621fbcb35a36 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -2275,7 +2275,7 @@ __kmem_cache_create (struct kmem_cache *cachep, unsigned long flags)
err = setup_cpu_cache(cachep, gfp);
if (err) {
- __kmem_cache_shutdown(cachep);
+ __kmem_cache_release(cachep);
return err;
}
@@ -2414,12 +2414,13 @@ int __kmem_cache_shrink(struct kmem_cache *cachep, bool deactivate)
int __kmem_cache_shutdown(struct kmem_cache *cachep)
{
+ return __kmem_cache_shrink(cachep, false);
+}
+
+void __kmem_cache_release(struct kmem_cache *cachep)
+{
int i;
struct kmem_cache_node *n;
- int rc = __kmem_cache_shrink(cachep, false);
-
- if (rc)
- return rc;
free_percpu(cachep->cpu_cache);
@@ -2430,7 +2431,6 @@ int __kmem_cache_shutdown(struct kmem_cache *cachep)
kfree(n);
cachep->node[i] = NULL;
}
- return 0;
}
/*