diff mbox series

[v2] mm/memcg: fix NULL pointer dereference in memcg_slab_free_hook()

Message ID 20210728145655.274476-1-wanghai38@huawei.com (mailing list archive)
State New
Headers show
Series [v2] mm/memcg: fix NULL pointer dereference in memcg_slab_free_hook() | expand

Commit Message

wanghai (M) July 28, 2021, 2:56 p.m. UTC
When I use kfree_rcu() to free a large memory allocated by
kmalloc_node(), the following dump occurs.

BUG: kernel NULL pointer dereference, address: 0000000000000020
[...]
Oops: 0000 [#1] SMP
[...]
Workqueue: events kfree_rcu_work
RIP: 0010:__obj_to_index include/linux/slub_def.h:182 [inline]
RIP: 0010:obj_to_index include/linux/slub_def.h:191 [inline]
RIP: 0010:memcg_slab_free_hook+0x120/0x260 mm/slab.h:363
[...]
Call Trace:
 kmem_cache_free_bulk+0x58/0x630 mm/slub.c:3293
 kfree_bulk include/linux/slab.h:413 [inline]
 kfree_rcu_work+0x1ab/0x200 kernel/rcu/tree.c:3300
 process_one_work+0x207/0x530 kernel/workqueue.c:2276
 worker_thread+0x320/0x610 kernel/workqueue.c:2422
 kthread+0x13d/0x160 kernel/kthread.c:313
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294

When kmalloc_node() a large memory, page is allocated, not slab,
so when freeing memory via kfree_rcu(), this large memory should not
be used by memcg_slab_free_hook(), because memcg_slab_free_hook() is
is used for slab.

Using page_objcgs_check() instead of page_objcgs() in
memcg_slab_free_hook() to fix this bug.

Fixes: 270c6a71460e ("mm: memcontrol/slab: Use helpers to access slab page's memcg_data")
Signed-off-by: Wang Hai <wanghai38@huawei.com>
---
v1->v2: Use page_objcgs_check() to fix this bug
 mm/slab.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Shakeel Butt July 28, 2021, 3:14 p.m. UTC | #1
On Wed, Jul 28, 2021 at 7:57 AM Wang Hai <wanghai38@huawei.com> wrote:
>
> When I use kfree_rcu() to free a large memory allocated by
> kmalloc_node(), the following dump occurs.
>
> BUG: kernel NULL pointer dereference, address: 0000000000000020
> [...]
> Oops: 0000 [#1] SMP
> [...]
> Workqueue: events kfree_rcu_work
> RIP: 0010:__obj_to_index include/linux/slub_def.h:182 [inline]
> RIP: 0010:obj_to_index include/linux/slub_def.h:191 [inline]
> RIP: 0010:memcg_slab_free_hook+0x120/0x260 mm/slab.h:363
> [...]
> Call Trace:
>  kmem_cache_free_bulk+0x58/0x630 mm/slub.c:3293
>  kfree_bulk include/linux/slab.h:413 [inline]
>  kfree_rcu_work+0x1ab/0x200 kernel/rcu/tree.c:3300
>  process_one_work+0x207/0x530 kernel/workqueue.c:2276
>  worker_thread+0x320/0x610 kernel/workqueue.c:2422
>  kthread+0x13d/0x160 kernel/kthread.c:313
>  ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294
>
> When kmalloc_node() a large memory, page is allocated, not slab,
> so when freeing memory via kfree_rcu(), this large memory should not
> be used by memcg_slab_free_hook(), because memcg_slab_free_hook() is
> is used for slab.
>
> Using page_objcgs_check() instead of page_objcgs() in
> memcg_slab_free_hook() to fix this bug.
>
> Fixes: 270c6a71460e ("mm: memcontrol/slab: Use helpers to access slab page's memcg_data")
> Signed-off-by: Wang Hai <wanghai38@huawei.com>

Reviewed-by: Shakeel Butt <shakeelb@google.com>
Michal Hocko July 28, 2021, 4:44 p.m. UTC | #2
On Wed 28-07-21 22:56:55, Wang Hai wrote:
> When I use kfree_rcu() to free a large memory allocated by
> kmalloc_node(), the following dump occurs.
> 
> BUG: kernel NULL pointer dereference, address: 0000000000000020
> [...]
> Oops: 0000 [#1] SMP
> [...]
> Workqueue: events kfree_rcu_work
> RIP: 0010:__obj_to_index include/linux/slub_def.h:182 [inline]
> RIP: 0010:obj_to_index include/linux/slub_def.h:191 [inline]
> RIP: 0010:memcg_slab_free_hook+0x120/0x260 mm/slab.h:363
> [...]
> Call Trace:
>  kmem_cache_free_bulk+0x58/0x630 mm/slub.c:3293
>  kfree_bulk include/linux/slab.h:413 [inline]
>  kfree_rcu_work+0x1ab/0x200 kernel/rcu/tree.c:3300
>  process_one_work+0x207/0x530 kernel/workqueue.c:2276
>  worker_thread+0x320/0x610 kernel/workqueue.c:2422
>  kthread+0x13d/0x160 kernel/kthread.c:313
>  ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294
> 
> When kmalloc_node() a large memory, page is allocated, not slab,
> so when freeing memory via kfree_rcu(), this large memory should not
> be used by memcg_slab_free_hook(), because memcg_slab_free_hook() is
> is used for slab.
> 
> Using page_objcgs_check() instead of page_objcgs() in
> memcg_slab_free_hook() to fix this bug.
> 
> Fixes: 270c6a71460e ("mm: memcontrol/slab: Use helpers to access slab page's memcg_data")
> Signed-off-by: Wang Hai <wanghai38@huawei.com>

This looks like a much better fix. Thanks!

Acked-by: Michal Hocko <mhocko@suse.com>

> ---
> v1->v2: Use page_objcgs_check() to fix this bug
>  mm/slab.h | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/mm/slab.h b/mm/slab.h
> index 67e06637ff2e..59db4797acd4 100644
> --- a/mm/slab.h
> +++ b/mm/slab.h
> @@ -339,7 +339,7 @@ static inline void memcg_slab_free_hook(struct kmem_cache *s_orig,
>  			continue;
>  
>  		page = virt_to_head_page(p[i]);
> -		objcgs = page_objcgs(page);
> +		objcgs = page_objcgs_check(page);
>  		if (!objcgs)
>  			continue;
>  
> -- 
> 2.17.1
Roman Gushchin July 28, 2021, 11:32 p.m. UTC | #3
On Wed, Jul 28, 2021 at 06:44:03PM +0200, Michal Hocko wrote:
> On Wed 28-07-21 22:56:55, Wang Hai wrote:
> > When I use kfree_rcu() to free a large memory allocated by
> > kmalloc_node(), the following dump occurs.
> > 
> > BUG: kernel NULL pointer dereference, address: 0000000000000020
> > [...]
> > Oops: 0000 [#1] SMP
> > [...]
> > Workqueue: events kfree_rcu_work
> > RIP: 0010:__obj_to_index include/linux/slub_def.h:182 [inline]
> > RIP: 0010:obj_to_index include/linux/slub_def.h:191 [inline]
> > RIP: 0010:memcg_slab_free_hook+0x120/0x260 mm/slab.h:363
> > [...]
> > Call Trace:
> >  kmem_cache_free_bulk+0x58/0x630 mm/slub.c:3293
> >  kfree_bulk include/linux/slab.h:413 [inline]
> >  kfree_rcu_work+0x1ab/0x200 kernel/rcu/tree.c:3300
> >  process_one_work+0x207/0x530 kernel/workqueue.c:2276
> >  worker_thread+0x320/0x610 kernel/workqueue.c:2422
> >  kthread+0x13d/0x160 kernel/kthread.c:313
> >  ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294
> > 
> > When kmalloc_node() a large memory, page is allocated, not slab,
> > so when freeing memory via kfree_rcu(), this large memory should not
> > be used by memcg_slab_free_hook(), because memcg_slab_free_hook() is
> > is used for slab.
> > 
> > Using page_objcgs_check() instead of page_objcgs() in
> > memcg_slab_free_hook() to fix this bug.
> > 
> > Fixes: 270c6a71460e ("mm: memcontrol/slab: Use helpers to access slab page's memcg_data")
> > Signed-off-by: Wang Hai <wanghai38@huawei.com>
> 
> This looks like a much better fix. Thanks!

+1

Acked-by: Roman Gushchin <guro@fb.com>

Thank you, Wang!
Muchun Song July 29, 2021, 6:03 a.m. UTC | #4
On Wed, Jul 28, 2021 at 10:57 PM Wang Hai <wanghai38@huawei.com> wrote:
>
> When I use kfree_rcu() to free a large memory allocated by
> kmalloc_node(), the following dump occurs.
>
> BUG: kernel NULL pointer dereference, address: 0000000000000020
> [...]
> Oops: 0000 [#1] SMP
> [...]
> Workqueue: events kfree_rcu_work
> RIP: 0010:__obj_to_index include/linux/slub_def.h:182 [inline]
> RIP: 0010:obj_to_index include/linux/slub_def.h:191 [inline]
> RIP: 0010:memcg_slab_free_hook+0x120/0x260 mm/slab.h:363
> [...]
> Call Trace:
>  kmem_cache_free_bulk+0x58/0x630 mm/slub.c:3293
>  kfree_bulk include/linux/slab.h:413 [inline]
>  kfree_rcu_work+0x1ab/0x200 kernel/rcu/tree.c:3300
>  process_one_work+0x207/0x530 kernel/workqueue.c:2276
>  worker_thread+0x320/0x610 kernel/workqueue.c:2422
>  kthread+0x13d/0x160 kernel/kthread.c:313
>  ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294
>
> When kmalloc_node() a large memory, page is allocated, not slab,
> so when freeing memory via kfree_rcu(), this large memory should not
> be used by memcg_slab_free_hook(), because memcg_slab_free_hook() is
> is used for slab.
>
> Using page_objcgs_check() instead of page_objcgs() in
> memcg_slab_free_hook() to fix this bug.
>
> Fixes: 270c6a71460e ("mm: memcontrol/slab: Use helpers to access slab page's memcg_data")
> Signed-off-by: Wang Hai <wanghai38@huawei.com>

More simpler than v1. Thanks.

Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Kefeng Wang July 29, 2021, 6:48 a.m. UTC | #5
On 2021/7/28 22:56, Wang Hai wrote:
> When I use kfree_rcu() to free a large memory allocated by
> kmalloc_node(), the following dump occurs.
>
> BUG: kernel NULL pointer dereference, address: 0000000000000020
> [...]
> Oops: 0000 [#1] SMP
> [...]
> Workqueue: events kfree_rcu_work
> RIP: 0010:__obj_to_index include/linux/slub_def.h:182 [inline]
> RIP: 0010:obj_to_index include/linux/slub_def.h:191 [inline]
> RIP: 0010:memcg_slab_free_hook+0x120/0x260 mm/slab.h:363
> [...]
> Call Trace:
>   kmem_cache_free_bulk+0x58/0x630 mm/slub.c:3293
>   kfree_bulk include/linux/slab.h:413 [inline]
>   kfree_rcu_work+0x1ab/0x200 kernel/rcu/tree.c:3300
>   process_one_work+0x207/0x530 kernel/workqueue.c:2276
>   worker_thread+0x320/0x610 kernel/workqueue.c:2422
>   kthread+0x13d/0x160 kernel/kthread.c:313
>   ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294
>
> When kmalloc_node() a large memory, page is allocated, not slab,
> so when freeing memory via kfree_rcu(), this large memory should not
> be used by memcg_slab_free_hook(), because memcg_slab_free_hook() is
> is used for slab.
>
> Using page_objcgs_check() instead of page_objcgs() in
> memcg_slab_free_hook() to fix this bug.
>
> Fixes: 270c6a71460e ("mm: memcontrol/slab: Use helpers to access slab page's memcg_data")
> Signed-off-by: Wang Hai <wanghai38@huawei.com>
Reviewed-by: Kefeng Wang <wangkefeng.wang@huawei.com>
> ---
> v1->v2: Use page_objcgs_check() to fix this bug
>   mm/slab.h | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/mm/slab.h b/mm/slab.h
> index 67e06637ff2e..59db4797acd4 100644
> --- a/mm/slab.h
> +++ b/mm/slab.h
> @@ -339,7 +339,7 @@ static inline void memcg_slab_free_hook(struct kmem_cache *s_orig,
>   			continue;
>   
>   		page = virt_to_head_page(p[i]);
> -		objcgs = page_objcgs(page);
> +		objcgs = page_objcgs_check(page);
>   		if (!objcgs)
>   			continue;
>
diff mbox series

Patch

diff --git a/mm/slab.h b/mm/slab.h
index 67e06637ff2e..59db4797acd4 100644
--- a/mm/slab.h
+++ b/mm/slab.h
@@ -339,7 +339,7 @@  static inline void memcg_slab_free_hook(struct kmem_cache *s_orig,
 			continue;
 
 		page = virt_to_head_page(p[i]);
-		objcgs = page_objcgs(page);
+		objcgs = page_objcgs_check(page);
 		if (!objcgs)
 			continue;