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author | 2016-02-17 13:11:37 -0800 | |
---|---|---|
committer | 2016-02-18 16:23:24 -0800 | |
commit | 52b4b950b50740bff507a62907e86710743c22e7 (patch) | |
tree | 16ec207435a99a4bc95482906acd8468fd322b82 | |
parent | ipc/shm: handle removed segments gracefully in shm_mmap() (diff) | |
download | linux-52b4b950b50740bff507a62907e86710743c22e7.tar.gz linux-52b4b950b50740bff507a62907e86710743c22e7.tar.bz2 linux-52b4b950b50740bff507a62907e86710743c22e7.zip |
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>
-rw-r--r-- | mm/slab.c | 12 | ||||
-rw-r--r-- | mm/slab.h | 1 | ||||
-rw-r--r-- | mm/slab_common.c | 1 | ||||
-rw-r--r-- | mm/slob.c | 4 | ||||
-rw-r--r-- | mm/slub.c | 38 |
5 files changed, 29 insertions, 27 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; } /* diff --git a/mm/slab.h b/mm/slab.h index 834ad240c0bb..2eedacea439d 100644 --- a/mm/slab.h +++ b/mm/slab.h @@ -140,6 +140,7 @@ static inline unsigned long kmem_cache_flags(unsigned long object_size, #define CACHE_CREATE_MASK (SLAB_CORE_FLAGS | SLAB_DEBUG_FLAGS | SLAB_CACHE_FLAGS) int __kmem_cache_shutdown(struct kmem_cache *); +void __kmem_cache_release(struct kmem_cache *); int __kmem_cache_shrink(struct kmem_cache *, bool); void slab_kmem_cache_release(struct kmem_cache *); diff --git a/mm/slab_common.c b/mm/slab_common.c index b50aef01ccf7..065b7bdabdc3 100644 --- a/mm/slab_common.c +++ b/mm/slab_common.c @@ -693,6 +693,7 @@ static inline int shutdown_memcg_caches(struct kmem_cache *s, void slab_kmem_cache_release(struct kmem_cache *s) { + __kmem_cache_release(s); destroy_memcg_params(s); kfree_const(s->name); kmem_cache_free(kmem_cache, s); diff --git a/mm/slob.c b/mm/slob.c index 17e8f8cc7c53..5ec158054ffe 100644 --- a/mm/slob.c +++ b/mm/slob.c @@ -630,6 +630,10 @@ int __kmem_cache_shutdown(struct kmem_cache *c) return 0; } +void __kmem_cache_release(struct kmem_cache *c) +{ +} + int __kmem_cache_shrink(struct kmem_cache *d, bool deactivate) { return 0; diff --git a/mm/slub.c b/mm/slub.c index 2e1355ac056b..d8fbd4a6ed59 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -1592,18 +1592,12 @@ static inline void add_partial(struct kmem_cache_node *n, __add_partial(n, page, tail); } -static inline void -__remove_partial(struct kmem_cache_node *n, struct page *page) -{ - list_del(&page->lru); - n->nr_partial--; -} - static inline void remove_partial(struct kmem_cache_node *n, struct page *page) { lockdep_assert_held(&n->list_lock); - __remove_partial(n, page); + list_del(&page->lru); + n->nr_partial--; } /* @@ -3184,6 +3178,12 @@ static void free_kmem_cache_nodes(struct kmem_cache *s) } } +void __kmem_cache_release(struct kmem_cache *s) +{ + free_percpu(s->cpu_slab); + free_kmem_cache_nodes(s); +} + static int init_kmem_cache_nodes(struct kmem_cache *s) { int node; @@ -3443,28 +3443,31 @@ static void list_slab_objects(struct kmem_cache *s, struct page *page, /* * Attempt to free all partial slabs on a node. - * This is called from kmem_cache_close(). We must be the last thread - * using the cache and therefore we do not need to lock anymore. + * This is called from __kmem_cache_shutdown(). We must take list_lock + * because sysfs file might still access partial list after the shutdowning. */ static void free_partial(struct kmem_cache *s, struct kmem_cache_node *n) { struct page *page, *h; + BUG_ON(irqs_disabled()); + spin_lock_irq(&n->list_lock); list_for_each_entry_safe(page, h, &n->partial, lru) { if (!page->inuse) { - __remove_partial(n, page); + remove_partial(n, page); discard_slab(s, page); } else { list_slab_objects(s, page, - "Objects remaining in %s on kmem_cache_close()"); + "Objects remaining in %s on __kmem_cache_shutdown()"); } } + spin_unlock_irq(&n->list_lock); } /* * Release all resources used by a slab cache. */ -static inline int kmem_cache_close(struct kmem_cache *s) +int __kmem_cache_shutdown(struct kmem_cache *s) { int node; struct kmem_cache_node *n; @@ -3476,16 +3479,9 @@ static inline int kmem_cache_close(struct kmem_cache *s) if (n->nr_partial || slabs_node(s, node)) return 1; } - free_percpu(s->cpu_slab); - free_kmem_cache_nodes(s); return 0; } -int __kmem_cache_shutdown(struct kmem_cache *s) -{ - return kmem_cache_close(s); -} - /******************************************************************** * Kmalloc subsystem *******************************************************************/ @@ -3980,7 +3976,7 @@ int __kmem_cache_create(struct kmem_cache *s, unsigned long flags) memcg_propagate_slab_attrs(s); err = sysfs_slab_add(s); if (err) - kmem_cache_close(s); + __kmem_cache_release(s); return err; } |