* [PATCH] cgroups: fix lock inconsistency in cgroup_clone()
@ 2009-01-20 6:43 Li Zefan
2009-01-21 10:05 ` Paul Menage
[not found] ` <497572AA.8020101-BthXqXjhjHXQFUHtdCDX3A@public.gmane.org>
0 siblings, 2 replies; 4+ messages in thread
From: Li Zefan @ 2009-01-20 6:43 UTC (permalink / raw)
To: Andrew Morton; +Cc: Paul Menage, LKML, Linux Containers
I fixed a bug in cgroup_clone() in Linus' tree (commit 7b574b7), without
noticing there was a cleanup patch in -mm tree that should be rebased
(now commit 104cbd5), thus resulted in lock inconsistency.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
---
for 2.6.29
---
kernel/cgroup.c | 13 +++++++------
1 files changed, 7 insertions(+), 6 deletions(-)
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index c298310..a5826f3 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -2991,20 +2991,21 @@ int cgroup_clone(struct task_struct *tsk, struct cgroup_subsys *subsys,
mutex_unlock(&cgroup_mutex);
return 0;
}
- task_lock(tsk);
- cg = tsk->cgroups;
- parent = task_cgroup(tsk, subsys->subsys_id);
/* Pin the hierarchy */
- if (!atomic_inc_not_zero(&parent->root->sb->s_active)) {
+ if (!atomic_inc_not_zero(&root->sb->s_active)) {
/* We race with the final deactivate_super() */
mutex_unlock(&cgroup_mutex);
return 0;
}
/* Keep the cgroup alive */
+ task_lock(tsk);
+ parent = task_cgroup(tsk, subsys->subsys_id);
+ cg = tsk->cgroups;
get_css_set(cg);
task_unlock(tsk);
+
mutex_unlock(&cgroup_mutex);
/* Now do the VFS work to create a cgroup */
@@ -3043,7 +3044,7 @@ int cgroup_clone(struct task_struct *tsk, struct cgroup_subsys *subsys,
mutex_unlock(&inode->i_mutex);
put_css_set(cg);
- deactivate_super(parent->root->sb);
+ deactivate_super(root->sb);
/* The cgroup is still accessible in the VFS, but
* we're not going to try to rmdir() it at this
* point. */
@@ -3069,7 +3070,7 @@ int cgroup_clone(struct task_struct *tsk, struct cgroup_subsys *subsys,
mutex_lock(&cgroup_mutex);
put_css_set(cg);
mutex_unlock(&cgroup_mutex);
- deactivate_super(parent->root->sb);
+ deactivate_super(root->sb);
return ret;
}
--
1.5.4.rc3
^ permalink raw reply related [flat|nested] 4+ messages in thread
* [PATCH] cgroups: fix lock inconsistency in cgroup_clone()
@ 2009-01-20 6:43 Li Zefan
0 siblings, 0 replies; 4+ messages in thread
From: Li Zefan @ 2009-01-20 6:43 UTC (permalink / raw)
To: Andrew Morton; +Cc: Linux Containers, Paul Menage, LKML
I fixed a bug in cgroup_clone() in Linus' tree (commit 7b574b7), without
noticing there was a cleanup patch in -mm tree that should be rebased
(now commit 104cbd5), thus resulted in lock inconsistency.
Signed-off-by: Li Zefan <lizf-BthXqXjhjHXQFUHtdCDX3A@public.gmane.org>
---
for 2.6.29
---
kernel/cgroup.c | 13 +++++++------
1 files changed, 7 insertions(+), 6 deletions(-)
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index c298310..a5826f3 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -2991,20 +2991,21 @@ int cgroup_clone(struct task_struct *tsk, struct cgroup_subsys *subsys,
mutex_unlock(&cgroup_mutex);
return 0;
}
- task_lock(tsk);
- cg = tsk->cgroups;
- parent = task_cgroup(tsk, subsys->subsys_id);
/* Pin the hierarchy */
- if (!atomic_inc_not_zero(&parent->root->sb->s_active)) {
+ if (!atomic_inc_not_zero(&root->sb->s_active)) {
/* We race with the final deactivate_super() */
mutex_unlock(&cgroup_mutex);
return 0;
}
/* Keep the cgroup alive */
+ task_lock(tsk);
+ parent = task_cgroup(tsk, subsys->subsys_id);
+ cg = tsk->cgroups;
get_css_set(cg);
task_unlock(tsk);
+
mutex_unlock(&cgroup_mutex);
/* Now do the VFS work to create a cgroup */
@@ -3043,7 +3044,7 @@ int cgroup_clone(struct task_struct *tsk, struct cgroup_subsys *subsys,
mutex_unlock(&inode->i_mutex);
put_css_set(cg);
- deactivate_super(parent->root->sb);
+ deactivate_super(root->sb);
/* The cgroup is still accessible in the VFS, but
* we're not going to try to rmdir() it at this
* point. */
@@ -3069,7 +3070,7 @@ int cgroup_clone(struct task_struct *tsk, struct cgroup_subsys *subsys,
mutex_lock(&cgroup_mutex);
put_css_set(cg);
mutex_unlock(&cgroup_mutex);
- deactivate_super(parent->root->sb);
+ deactivate_super(root->sb);
return ret;
}
--
1.5.4.rc3
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH] cgroups: fix lock inconsistency in cgroup_clone()
[not found] ` <497572AA.8020101-BthXqXjhjHXQFUHtdCDX3A@public.gmane.org>
@ 2009-01-21 10:05 ` Paul Menage
0 siblings, 0 replies; 4+ messages in thread
From: Paul Menage @ 2009-01-21 10:05 UTC (permalink / raw)
To: Li Zefan; +Cc: Linux Containers, Andrew Morton, LKML
On Mon, Jan 19, 2009 at 10:43 PM, Li Zefan <lizf-BthXqXjhjHXQFUHtdCDX3A@public.gmane.org> wrote:
> I fixed a bug in cgroup_clone() in Linus' tree (commit 7b574b7), without
> noticing there was a cleanup patch in -mm tree that should be rebased
> (now commit 104cbd5), thus resulted in lock inconsistency.
>
> Signed-off-by: Li Zefan <lizf-BthXqXjhjHXQFUHtdCDX3A@public.gmane.org>
Acked-by: Paul Menage <menage-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
Thanks.
> ---
>
> for 2.6.29
>
> ---
> kernel/cgroup.c | 13 +++++++------
> 1 files changed, 7 insertions(+), 6 deletions(-)
>
> diff --git a/kernel/cgroup.c b/kernel/cgroup.c
> index c298310..a5826f3 100644
> --- a/kernel/cgroup.c
> +++ b/kernel/cgroup.c
> @@ -2991,20 +2991,21 @@ int cgroup_clone(struct task_struct *tsk, struct cgroup_subsys *subsys,
> mutex_unlock(&cgroup_mutex);
> return 0;
> }
> - task_lock(tsk);
> - cg = tsk->cgroups;
> - parent = task_cgroup(tsk, subsys->subsys_id);
>
> /* Pin the hierarchy */
> - if (!atomic_inc_not_zero(&parent->root->sb->s_active)) {
> + if (!atomic_inc_not_zero(&root->sb->s_active)) {
> /* We race with the final deactivate_super() */
> mutex_unlock(&cgroup_mutex);
> return 0;
> }
>
> /* Keep the cgroup alive */
> + task_lock(tsk);
> + parent = task_cgroup(tsk, subsys->subsys_id);
> + cg = tsk->cgroups;
> get_css_set(cg);
> task_unlock(tsk);
> +
> mutex_unlock(&cgroup_mutex);
>
> /* Now do the VFS work to create a cgroup */
> @@ -3043,7 +3044,7 @@ int cgroup_clone(struct task_struct *tsk, struct cgroup_subsys *subsys,
> mutex_unlock(&inode->i_mutex);
> put_css_set(cg);
>
> - deactivate_super(parent->root->sb);
> + deactivate_super(root->sb);
> /* The cgroup is still accessible in the VFS, but
> * we're not going to try to rmdir() it at this
> * point. */
> @@ -3069,7 +3070,7 @@ int cgroup_clone(struct task_struct *tsk, struct cgroup_subsys *subsys,
> mutex_lock(&cgroup_mutex);
> put_css_set(cg);
> mutex_unlock(&cgroup_mutex);
> - deactivate_super(parent->root->sb);
> + deactivate_super(root->sb);
> return ret;
> }
>
> --
> 1.5.4.rc3
>
>
>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] cgroups: fix lock inconsistency in cgroup_clone()
2009-01-20 6:43 [PATCH] cgroups: fix lock inconsistency in cgroup_clone() Li Zefan
@ 2009-01-21 10:05 ` Paul Menage
[not found] ` <497572AA.8020101-BthXqXjhjHXQFUHtdCDX3A@public.gmane.org>
1 sibling, 0 replies; 4+ messages in thread
From: Paul Menage @ 2009-01-21 10:05 UTC (permalink / raw)
To: Li Zefan; +Cc: Andrew Morton, LKML, Linux Containers
On Mon, Jan 19, 2009 at 10:43 PM, Li Zefan <lizf@cn.fujitsu.com> wrote:
> I fixed a bug in cgroup_clone() in Linus' tree (commit 7b574b7), without
> noticing there was a cleanup patch in -mm tree that should be rebased
> (now commit 104cbd5), thus resulted in lock inconsistency.
>
> Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Paul Menage <menage@google.com>
Thanks.
> ---
>
> for 2.6.29
>
> ---
> kernel/cgroup.c | 13 +++++++------
> 1 files changed, 7 insertions(+), 6 deletions(-)
>
> diff --git a/kernel/cgroup.c b/kernel/cgroup.c
> index c298310..a5826f3 100644
> --- a/kernel/cgroup.c
> +++ b/kernel/cgroup.c
> @@ -2991,20 +2991,21 @@ int cgroup_clone(struct task_struct *tsk, struct cgroup_subsys *subsys,
> mutex_unlock(&cgroup_mutex);
> return 0;
> }
> - task_lock(tsk);
> - cg = tsk->cgroups;
> - parent = task_cgroup(tsk, subsys->subsys_id);
>
> /* Pin the hierarchy */
> - if (!atomic_inc_not_zero(&parent->root->sb->s_active)) {
> + if (!atomic_inc_not_zero(&root->sb->s_active)) {
> /* We race with the final deactivate_super() */
> mutex_unlock(&cgroup_mutex);
> return 0;
> }
>
> /* Keep the cgroup alive */
> + task_lock(tsk);
> + parent = task_cgroup(tsk, subsys->subsys_id);
> + cg = tsk->cgroups;
> get_css_set(cg);
> task_unlock(tsk);
> +
> mutex_unlock(&cgroup_mutex);
>
> /* Now do the VFS work to create a cgroup */
> @@ -3043,7 +3044,7 @@ int cgroup_clone(struct task_struct *tsk, struct cgroup_subsys *subsys,
> mutex_unlock(&inode->i_mutex);
> put_css_set(cg);
>
> - deactivate_super(parent->root->sb);
> + deactivate_super(root->sb);
> /* The cgroup is still accessible in the VFS, but
> * we're not going to try to rmdir() it at this
> * point. */
> @@ -3069,7 +3070,7 @@ int cgroup_clone(struct task_struct *tsk, struct cgroup_subsys *subsys,
> mutex_lock(&cgroup_mutex);
> put_css_set(cg);
> mutex_unlock(&cgroup_mutex);
> - deactivate_super(parent->root->sb);
> + deactivate_super(root->sb);
> return ret;
> }
>
> --
> 1.5.4.rc3
>
>
>
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2009-01-21 10:06 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz follow: Atom feed
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2009-01-20 6:43 [PATCH] cgroups: fix lock inconsistency in cgroup_clone() Li Zefan
2009-01-21 10:05 ` Paul Menage
[not found] ` <497572AA.8020101-BthXqXjhjHXQFUHtdCDX3A@public.gmane.org>
2009-01-21 10:05 ` Paul Menage
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