From: Xiu Jianfeng Date: Wed, 24 May 2023 06:54:31 +0000 (+0800) Subject: cgroup: Update out-of-date comment in cgroup_migrate() X-Git-Tag: v6.5-rc1~187^2~10 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=659db0789c2e66c5d6a52d57008e3a7401a3ffff;p=thirdparty%2Flinux.git cgroup: Update out-of-date comment in cgroup_migrate() Commit 674b745e22b3 ("cgroup: remove rcu_read_lock()/rcu_read_unlock() in critical section of spin_lock_irq()") has removed the rcu_read_lock, which makes the comment out-of-date, so update it. tj: Updated the comment a bit. Signed-off-by: Xiu Jianfeng Signed-off-by: Tejun Heo --- diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c index 9d809191a54f1..f329f49529a2c 100644 --- a/kernel/cgroup/cgroup.c +++ b/kernel/cgroup/cgroup.c @@ -2872,9 +2872,9 @@ int cgroup_migrate(struct task_struct *leader, bool threadgroup, struct task_struct *task; /* - * Prevent freeing of tasks while we take a snapshot. Tasks that are - * already PF_EXITING could be freed from underneath us unless we - * take an rcu_read_lock. + * The following thread iteration should be inside an RCU critical + * section to prevent tasks from being freed while taking the snapshot. + * spin_lock_irq() implies RCU critical section here. */ spin_lock_irq(&css_set_lock); task = leader;