* [PATCH] mm/slab: fix race with dereferencing NULL ptr in alloc_calls_show
@ 2016-02-02 15:01 ` Dmitry Safonov
0 siblings, 0 replies; 6+ messages in thread
From: Dmitry Safonov @ 2016-02-02 15:01 UTC (permalink / raw)
To: akpm, cl, penberg, rientjes, iamjoonsoo.kim
Cc: linux-mm, linux-kernel, Dmitry Safonov, Vladimir Davydov
memcg_destroy_kmem_caches shutdowns in the first place kmem_caches under
slab_mutex which involves freeing NUMA node structures for kmem_cache
and only then under release_caches removes corresponding sysfs files for
these caches. Which may lead to dereferencing NULL ptr on read.
Lets remove sysfs files right there.
Fixes the following panic:
[43963.463055] BUG: unable to handle kernel
[43963.463090] NULL pointer dereference at 0000000000000020
[43963.463146] IP: [<ffffffff811c6959>] list_locations+0x169/0x4e0
[43963.463185] PGD 257304067 PUD 438456067 PMD 0
[43963.463220] Oops: 0000 [#1] SMP
[43963.463850] 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
[43963.463913] Hardware name: DEPO Computers To Be Filled By O.E.M./H67DE3, BIOS L1.60c 07/14/2011
[43963.463976] task: ffff88042a5dc5b0 ti: ffff88037f8d8000 task.ti: ffff88037f8d8000
[43963.464036] RIP: 0010:[<ffffffff811c6959>] [<ffffffff811c6959>] list_locations+0x169/0x4e0
[43963.464725] Call Trace:
[43963.464756] [<ffffffff811c6d1d>] alloc_calls_show+0x1d/0x30
[43963.464793] [<ffffffff811c15ab>] slab_attr_show+0x1b/0x30
[43963.464829] [<ffffffff8125d27a>] sysfs_read_file+0x9a/0x1a0
[43963.464865] [<ffffffff811e3c6c>] vfs_read+0x9c/0x170
[43963.464900] [<ffffffff811e4798>] SyS_read+0x58/0xb0
[43963.464936] [<ffffffff81612d49>] system_call_fastpath+0x16/0x1b
[43963.464970] 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
[43963.465119] RIP [<ffffffff811c6959>] list_locations+0x169/0x4e0
[43963.465155] RSP <ffff88037f8dbe28>
[43963.465185] CR2: 0000000000000020
Cc: Vladimir Davydov <vdavydov@virtuozzo.com>
Signed-off-by: Dmitry Safonov <dsafonov@virtuozzo.com>
---
mm/slab_common.c | 10 ++++------
mm/slub.c | 6 ------
2 files changed, 4 insertions(+), 12 deletions(-)
diff --git a/mm/slab_common.c b/mm/slab_common.c
index b50aef0..6725eb3 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -468,13 +468,8 @@ static void release_caches(struct list_head *release, bool need_rcu_barrier)
if (need_rcu_barrier)
rcu_barrier();
- list_for_each_entry_safe(s, s2, release, list) {
-#ifdef SLAB_SUPPORTS_SYSFS
- sysfs_slab_remove(s);
-#else
+ list_for_each_entry_safe(s, s2, release, list)
slab_kmem_cache_release(s);
-#endif
- }
}
#if defined(CONFIG_MEMCG) && !defined(CONFIG_SLOB)
@@ -614,6 +609,9 @@ void memcg_destroy_kmem_caches(struct mem_cgroup *memcg)
list_for_each_entry_safe(s, s2, &slab_caches, list) {
if (is_root_cache(s) || s->memcg_params.memcg != memcg)
continue;
+
+ sysfs_slab_remove(s);
+
/*
* The cgroup is about to be freed and therefore has no charges
* left. Hence, all its caches must be empty by now.
diff --git a/mm/slub.c b/mm/slub.c
index 2e1355a..b6a68b7 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -5296,11 +5296,6 @@ static void memcg_propagate_slab_attrs(struct kmem_cache *s)
#endif
}
-static void kmem_cache_release(struct kobject *k)
-{
- slab_kmem_cache_release(to_slab(k));
-}
-
static const struct sysfs_ops slab_sysfs_ops = {
.show = slab_attr_show,
.store = slab_attr_store,
@@ -5308,7 +5303,6 @@ static const struct sysfs_ops slab_sysfs_ops = {
static struct kobj_type slab_ktype = {
.sysfs_ops = &slab_sysfs_ops,
- .release = kmem_cache_release,
};
static int uevent_filter(struct kset *kset, struct kobject *kobj)
--
2.7.0
^ permalink raw reply related [flat|nested] 6+ messages in thread
* [PATCH] mm/slab: fix race with dereferencing NULL ptr in alloc_calls_show
@ 2016-02-02 15:01 ` Dmitry Safonov
0 siblings, 0 replies; 6+ messages in thread
From: Dmitry Safonov @ 2016-02-02 15:01 UTC (permalink / raw)
To: akpm, cl, penberg, rientjes, iamjoonsoo.kim
Cc: linux-mm, linux-kernel, Dmitry Safonov, Vladimir Davydov
memcg_destroy_kmem_caches shutdowns in the first place kmem_caches under
slab_mutex which involves freeing NUMA node structures for kmem_cache
and only then under release_caches removes corresponding sysfs files for
these caches. Which may lead to dereferencing NULL ptr on read.
Lets remove sysfs files right there.
Fixes the following panic:
[43963.463055] BUG: unable to handle kernel
[43963.463090] NULL pointer dereference at 0000000000000020
[43963.463146] IP: [<ffffffff811c6959>] list_locations+0x169/0x4e0
[43963.463185] PGD 257304067 PUD 438456067 PMD 0
[43963.463220] Oops: 0000 [#1] SMP
[43963.463850] 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
[43963.463913] Hardware name: DEPO Computers To Be Filled By O.E.M./H67DE3, BIOS L1.60c 07/14/2011
[43963.463976] task: ffff88042a5dc5b0 ti: ffff88037f8d8000 task.ti: ffff88037f8d8000
[43963.464036] RIP: 0010:[<ffffffff811c6959>] [<ffffffff811c6959>] list_locations+0x169/0x4e0
[43963.464725] Call Trace:
[43963.464756] [<ffffffff811c6d1d>] alloc_calls_show+0x1d/0x30
[43963.464793] [<ffffffff811c15ab>] slab_attr_show+0x1b/0x30
[43963.464829] [<ffffffff8125d27a>] sysfs_read_file+0x9a/0x1a0
[43963.464865] [<ffffffff811e3c6c>] vfs_read+0x9c/0x170
[43963.464900] [<ffffffff811e4798>] SyS_read+0x58/0xb0
[43963.464936] [<ffffffff81612d49>] system_call_fastpath+0x16/0x1b
[43963.464970] 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
[43963.465119] RIP [<ffffffff811c6959>] list_locations+0x169/0x4e0
[43963.465155] RSP <ffff88037f8dbe28>
[43963.465185] CR2: 0000000000000020
Cc: Vladimir Davydov <vdavydov@virtuozzo.com>
Signed-off-by: Dmitry Safonov <dsafonov@virtuozzo.com>
---
mm/slab_common.c | 10 ++++------
mm/slub.c | 6 ------
2 files changed, 4 insertions(+), 12 deletions(-)
diff --git a/mm/slab_common.c b/mm/slab_common.c
index b50aef0..6725eb3 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -468,13 +468,8 @@ static void release_caches(struct list_head *release, bool need_rcu_barrier)
if (need_rcu_barrier)
rcu_barrier();
- list_for_each_entry_safe(s, s2, release, list) {
-#ifdef SLAB_SUPPORTS_SYSFS
- sysfs_slab_remove(s);
-#else
+ list_for_each_entry_safe(s, s2, release, list)
slab_kmem_cache_release(s);
-#endif
- }
}
#if defined(CONFIG_MEMCG) && !defined(CONFIG_SLOB)
@@ -614,6 +609,9 @@ void memcg_destroy_kmem_caches(struct mem_cgroup *memcg)
list_for_each_entry_safe(s, s2, &slab_caches, list) {
if (is_root_cache(s) || s->memcg_params.memcg != memcg)
continue;
+
+ sysfs_slab_remove(s);
+
/*
* The cgroup is about to be freed and therefore has no charges
* left. Hence, all its caches must be empty by now.
diff --git a/mm/slub.c b/mm/slub.c
index 2e1355a..b6a68b7 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -5296,11 +5296,6 @@ static void memcg_propagate_slab_attrs(struct kmem_cache *s)
#endif
}
-static void kmem_cache_release(struct kobject *k)
-{
- slab_kmem_cache_release(to_slab(k));
-}
-
static const struct sysfs_ops slab_sysfs_ops = {
.show = slab_attr_show,
.store = slab_attr_store,
@@ -5308,7 +5303,6 @@ static const struct sysfs_ops slab_sysfs_ops = {
static struct kobj_type slab_ktype = {
.sysfs_ops = &slab_sysfs_ops,
- .release = kmem_cache_release,
};
static int uevent_filter(struct kset *kset, struct kobject *kobj)
--
2.7.0
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
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^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH] mm/slab: fix race with dereferencing NULL ptr in alloc_calls_show
2016-02-02 15:01 ` Dmitry Safonov
@ 2016-02-02 15:19 ` kbuild test robot
-1 siblings, 0 replies; 6+ messages in thread
From: kbuild test robot @ 2016-02-02 15:19 UTC (permalink / raw)
To: Dmitry Safonov
Cc: kbuild-all, akpm, cl, penberg, rientjes, iamjoonsoo.kim,
linux-mm, linux-kernel, Dmitry Safonov, Vladimir Davydov
[-- Attachment #1: Type: text/plain, Size: 1327 bytes --]
Hi Dmitry,
[auto build test ERROR on v4.5-rc2]
[also build test ERROR on next-20160201]
[if your patch is applied to the wrong git tree, please drop us a note to help improving the system]
url: https://github.com/0day-ci/linux/commits/Dmitry-Safonov/mm-slab-fix-race-with-dereferencing-NULL-ptr-in-alloc_calls_show/20160202-230449
config: i386-randconfig-x005-02010231 (attached as .config)
reproduce:
# save the attached .config to linux build tree
make ARCH=i386
All errors (new ones prefixed by >>):
mm/slab_common.c: In function 'memcg_destroy_kmem_caches':
>> mm/slab_common.c:613:3: error: implicit declaration of function 'sysfs_slab_remove' [-Werror=implicit-function-declaration]
sysfs_slab_remove(s);
^
cc1: some warnings being treated as errors
vim +/sysfs_slab_remove +613 mm/slab_common.c
607
608 mutex_lock(&slab_mutex);
609 list_for_each_entry_safe(s, s2, &slab_caches, list) {
610 if (is_root_cache(s) || s->memcg_params.memcg != memcg)
611 continue;
612
> 613 sysfs_slab_remove(s);
614
615 /*
616 * The cgroup is about to be freed and therefore has no charges
---
0-DAY kernel test infrastructure Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all Intel Corporation
[-- Attachment #2: .config.gz --]
[-- Type: application/octet-stream, Size: 25271 bytes --]
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] mm/slab: fix race with dereferencing NULL ptr in alloc_calls_show
@ 2016-02-02 15:19 ` kbuild test robot
0 siblings, 0 replies; 6+ messages in thread
From: kbuild test robot @ 2016-02-02 15:19 UTC (permalink / raw)
To: Dmitry Safonov
Cc: kbuild-all, akpm, cl, penberg, rientjes, iamjoonsoo.kim,
linux-mm, linux-kernel, Vladimir Davydov
[-- Attachment #1: Type: text/plain, Size: 1327 bytes --]
Hi Dmitry,
[auto build test ERROR on v4.5-rc2]
[also build test ERROR on next-20160201]
[if your patch is applied to the wrong git tree, please drop us a note to help improving the system]
url: https://github.com/0day-ci/linux/commits/Dmitry-Safonov/mm-slab-fix-race-with-dereferencing-NULL-ptr-in-alloc_calls_show/20160202-230449
config: i386-randconfig-x005-02010231 (attached as .config)
reproduce:
# save the attached .config to linux build tree
make ARCH=i386
All errors (new ones prefixed by >>):
mm/slab_common.c: In function 'memcg_destroy_kmem_caches':
>> mm/slab_common.c:613:3: error: implicit declaration of function 'sysfs_slab_remove' [-Werror=implicit-function-declaration]
sysfs_slab_remove(s);
^
cc1: some warnings being treated as errors
vim +/sysfs_slab_remove +613 mm/slab_common.c
607
608 mutex_lock(&slab_mutex);
609 list_for_each_entry_safe(s, s2, &slab_caches, list) {
610 if (is_root_cache(s) || s->memcg_params.memcg != memcg)
611 continue;
612
> 613 sysfs_slab_remove(s);
614
615 /*
616 * The cgroup is about to be freed and therefore has no charges
---
0-DAY kernel test infrastructure Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all Intel Corporation
[-- Attachment #2: .config.gz --]
[-- Type: application/octet-stream, Size: 25271 bytes --]
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] mm/slab: fix race with dereferencing NULL ptr in alloc_calls_show
2016-02-02 15:19 ` kbuild test robot
@ 2016-02-02 15:55 ` Dmitry Safonov
-1 siblings, 0 replies; 6+ messages in thread
From: Dmitry Safonov @ 2016-02-02 15:55 UTC (permalink / raw)
To: kbuild test robot
Cc: kbuild-all, akpm, cl, penberg, rientjes, iamjoonsoo.kim,
linux-mm, linux-kernel, Vladimir Davydov
On 02/02/2016 06:19 PM, kbuild test robot wrote:
> Hi Dmitry,
>
> [auto build test ERROR on v4.5-rc2]
> [also build test ERROR on next-20160201]
> [if your patch is applied to the wrong git tree, please drop us a note to help improving the system]
>
> url: https://github.com/0day-ci/linux/commits/Dmitry-Safonov/mm-slab-fix-race-with-dereferencing-NULL-ptr-in-alloc_calls_show/20160202-230449
> config: i386-randconfig-x005-02010231 (attached as .config)
> reproduce:
> # save the attached .config to linux build tree
> make ARCH=i386
Thanks little robot, will resend fixed v2 right soon.
>
> All errors (new ones prefixed by >>):
>
> mm/slab_common.c: In function 'memcg_destroy_kmem_caches':
>>> mm/slab_common.c:613:3: error: implicit declaration of function 'sysfs_slab_remove' [-Werror=implicit-function-declaration]
> sysfs_slab_remove(s);
> ^
> cc1: some warnings being treated as errors
>
> vim +/sysfs_slab_remove +613 mm/slab_common.c
>
> 607
> 608 mutex_lock(&slab_mutex);
> 609 list_for_each_entry_safe(s, s2, &slab_caches, list) {
> 610 if (is_root_cache(s) || s->memcg_params.memcg != memcg)
> 611 continue;
> 612
> > 613 sysfs_slab_remove(s);
> 614
> 615 /*
> 616 * The cgroup is about to be freed and therefore has no charges
>
> ---
> 0-DAY kernel test infrastructure Open Source Technology Center
> https://lists.01.org/pipermail/kbuild-all Intel Corporation
--
Regards,
Dmitry Safonov
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] mm/slab: fix race with dereferencing NULL ptr in alloc_calls_show
@ 2016-02-02 15:55 ` Dmitry Safonov
0 siblings, 0 replies; 6+ messages in thread
From: Dmitry Safonov @ 2016-02-02 15:55 UTC (permalink / raw)
To: kbuild test robot
Cc: kbuild-all, akpm, cl, penberg, rientjes, iamjoonsoo.kim,
linux-mm, linux-kernel, Vladimir Davydov
On 02/02/2016 06:19 PM, kbuild test robot wrote:
> Hi Dmitry,
>
> [auto build test ERROR on v4.5-rc2]
> [also build test ERROR on next-20160201]
> [if your patch is applied to the wrong git tree, please drop us a note to help improving the system]
>
> url: https://github.com/0day-ci/linux/commits/Dmitry-Safonov/mm-slab-fix-race-with-dereferencing-NULL-ptr-in-alloc_calls_show/20160202-230449
> config: i386-randconfig-x005-02010231 (attached as .config)
> reproduce:
> # save the attached .config to linux build tree
> make ARCH=i386
Thanks little robot, will resend fixed v2 right soon.
>
> All errors (new ones prefixed by >>):
>
> mm/slab_common.c: In function 'memcg_destroy_kmem_caches':
>>> mm/slab_common.c:613:3: error: implicit declaration of function 'sysfs_slab_remove' [-Werror=implicit-function-declaration]
> sysfs_slab_remove(s);
> ^
> cc1: some warnings being treated as errors
>
> vim +/sysfs_slab_remove +613 mm/slab_common.c
>
> 607
> 608 mutex_lock(&slab_mutex);
> 609 list_for_each_entry_safe(s, s2, &slab_caches, list) {
> 610 if (is_root_cache(s) || s->memcg_params.memcg != memcg)
> 611 continue;
> 612
> > 613 sysfs_slab_remove(s);
> 614
> 615 /*
> 616 * The cgroup is about to be freed and therefore has no charges
>
> ---
> 0-DAY kernel test infrastructure Open Source Technology Center
> https://lists.01.org/pipermail/kbuild-all Intel Corporation
--
Regards,
Dmitry Safonov
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
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see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2016-02-02 15:55 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2016-02-02 15:01 [PATCH] mm/slab: fix race with dereferencing NULL ptr in alloc_calls_show Dmitry Safonov
2016-02-02 15:01 ` Dmitry Safonov
2016-02-02 15:19 ` kbuild test robot
2016-02-02 15:19 ` kbuild test robot
2016-02-02 15:55 ` Dmitry Safonov
2016-02-02 15:55 ` Dmitry Safonov
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