Hello, I further edited the comment and applied the patch to cgroup/for-6.5 Thanks. >From 659db0789c2e66c5d6a52d57008e3a7401a3ffff Mon Sep 17 00:00:00 2001 From: Xiu Jianfeng <xiujianfeng@xxxxxxxxxxxxxxx> Date: Wed, 24 May 2023 14:54:31 +0800 Subject: [PATCH] cgroup: Update out-of-date comment in cgroup_migrate() Commit 674b745e22b3 ("cgroup: remove rcu_read_lock()/rcu_read_unlock() in critical section of spin_lock_irq()") has removed the rcu_read_lock, which makes the comment out-of-date, so update it.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 <xiujianfeng@xxxxxxxxxx> Signed-off-by: Tejun Heo <tj@xxxxxxxxxx> --- kernel/cgroup/cgroup.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c index 9d809191a54f..f329f49529a2 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; -- 2.40.1