From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id CAC7F2566 for ; Tue, 18 Apr 2023 12:28:59 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4D593C433EF; Tue, 18 Apr 2023 12:28:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1681820939; bh=5JXf1puGAOyrl+VZGSEHoiMyiGjva/OyHYhZo7RWGdY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=zIEsf9aymTA4tZT0ft0B2C8UOQWquiLwFCzIkKoqyr2IBOhAM2PaBHMpq1XtIXbnL aYvmX3TfnSvpa5wA+fe5evwFWxorq0y2fWBusNW58MivRqt6Pw2r5CmvsWVIYz1gnj UloiCrVeYJ+2cqMhbTQqc9kvtZCNn3eof9mCH7m4= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Waiman Long , =?UTF-8?q?Michal=20Koutn=C3=BD?= , Tejun Heo Subject: [PATCH 5.4 03/92] cgroup/cpuset: Wake up cpuset_attach_wq tasks in cpuset_cancel_attach() Date: Tue, 18 Apr 2023 14:20:38 +0200 Message-Id: <20230418120304.817812245@linuxfoundation.org> X-Mailer: git-send-email 2.40.0 In-Reply-To: <20230418120304.658273364@linuxfoundation.org> References: <20230418120304.658273364@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Waiman Long 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 Reviewed-by: Michal Koutný Cc: stable@vger.kernel.org # v3.11+ Signed-off-by: Tejun Heo Signed-off-by: Greg Kroah-Hartman --- kernel/cgroup/cpuset.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) --- a/kernel/cgroup/cpuset.c +++ b/kernel/cgroup/cpuset.c @@ -2180,11 +2180,15 @@ out_unlock: static void cpuset_cancel_attach(struct cgroup_taskset *tset) { struct cgroup_subsys_state *css; + struct cpuset *cs; cgroup_taskset_first(tset, &css); + cs = css_cs(css); percpu_down_write(&cpuset_rwsem); - css_cs(css)->attach_in_progress--; + cs->attach_in_progress--; + if (!cs->attach_in_progress) + wake_up(&cpuset_attach_wq); percpu_up_write(&cpuset_rwsem); }