From: Tejun Heo <tj@kernel.org>
To: Neeraj Upadhyay <neeraju@codeaurora.org>
Cc: lizefan@huawei.com, mingo@kernel.org, longman@redhat.com,
akpm@linux-foundation.org, linux-kernel@vger.kernel.org,
sramana@codeaurora.org, prsood@codeaurora.org
Subject: Re: [PATCH] cgroup: Fix potential race between cgroup_exit and migrate path
Date: Wed, 30 Aug 2017 18:03:19 -0700 [thread overview]
Message-ID: <20170831010319.GB491396@devbig577.frc2.facebook.com> (raw)
In-Reply-To: <20170831005545.GA491396@devbig577.frc2.facebook.com>
On Wed, Aug 30, 2017 at 05:55:45PM -0700, Tejun Heo wrote:
> Would something like the following fix the issue? Thanks.
>
> diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c
> index df2e0f1..cd85ca0 100644
> --- a/kernel/cgroup/cgroup.c
> +++ b/kernel/cgroup/cgroup.c
> @@ -683,7 +683,7 @@ static void css_set_move_task(struct task_struct *task,
> if (it->task_pos == &task->cg_list)
> css_task_iter_advance(it);
>
> - list_del_init(&task->cg_list);
> + list_del(&task->cg_list);
> if (!css_set_populated(from_cset))
> css_set_update_populated(from_cset, false);
> } else {
Oops, more like the following.
diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c
index df2e0f1..6f34025 100644
--- a/kernel/cgroup/cgroup.c
+++ b/kernel/cgroup/cgroup.c
@@ -683,7 +683,7 @@ static void css_set_move_task(struct task_struct *task,
if (it->task_pos == &task->cg_list)
css_task_iter_advance(it);
- list_del_init(&task->cg_list);
+ list_del(&task->cg_list);
if (!css_set_populated(from_cset))
css_set_update_populated(from_cset, false);
} else {
@@ -702,6 +702,8 @@ static void css_set_move_task(struct task_struct *task,
rcu_assign_pointer(task->cgroups, to_cset);
list_add_tail(&task->cg_list, use_mg_tasks ? &to_cset->mg_tasks :
&to_cset->tasks);
+ } else {
+ INIT_LIST_HEAD(&task->cg_list);
}
}
next prev parent reply other threads:[~2017-08-31 1:03 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-08-30 12:54 [PATCH] cgroup: Fix potential race between cgroup_exit and migrate path Neeraj Upadhyay
2017-08-31 0:55 ` Tejun Heo
2017-08-31 1:03 ` Tejun Heo [this message]
2017-08-31 1:12 ` Tejun Heo
2017-09-04 13:23 ` Neeraj Upadhyay
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