This is a note to let you know that I've just added the patch titled
cgroup/cpuset: Wake up cpuset_attach_wq tasks in cpuset_cancel_attach()
to the 4.19-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
cgroup-cpuset-wake-up-cpuset_attach_wq-tasks-in-cpuset_cancel_attach.patch
and it can be found in the queue-4.19 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From ba9182a89626d5f83c2ee4594f55cb9c1e60f0e2 Mon Sep 17 00:00:00 2001
From: Waiman Long <longman@xxxxxxxxxx>
Date: Tue, 11 Apr 2023 09:35:57 -0400
Subject: cgroup/cpuset: Wake up cpuset_attach_wq tasks in cpuset_cancel_attach()
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From: Waiman Long <longman@xxxxxxxxxx>
commit ba9182a89626d5f83c2ee4594f55cb9c1e60f0e2 upstream.
After a successful cpuset_can_attach() call which increments the
attach_in_progress flag, either cpuset_cancel_attach() or cpuset_attach()
will be called later. In cpuset_attach(), tasks in cpuset_attach_wq,
if present, will be woken up at the end. That is not the case in
cpuset_cancel_attach(). So missed wakeup is possible if the attach
operation is somehow cancelled. Fix that by doing the wakeup in
cpuset_cancel_attach() as well.
Fixes: e44193d39e8d ("cpuset: let hotplug propagation work wait for task attaching")
Signed-off-by: Waiman Long <longman@xxxxxxxxxx>
Reviewed-by: Michal Koutný <mkoutny@xxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx # v3.11+
Signed-off-by: Tejun Heo <tj@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
kernel/cgroup/cpuset.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
--- a/kernel/cgroup/cpuset.c
+++ b/kernel/cgroup/cpuset.c
@@ -1504,7 +1504,9 @@ static void cpuset_cancel_attach(struct
cs = css_cs(css);
mutex_lock(&cpuset_mutex);
- css_cs(css)->attach_in_progress--;
+ cs->attach_in_progress--;
+ if (!cs->attach_in_progress)
+ wake_up(&cpuset_attach_wq);
mutex_unlock(&cpuset_mutex);
}
Patches currently in stable-queue which might be from longman@xxxxxxxxxx are
queue-4.19/cgroup-cpuset-wake-up-cpuset_attach_wq-tasks-in-cpuset_cancel_attach.patch
