Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S935601AbdLSNkF (ORCPT ); Tue, 19 Dec 2017 08:40:05 -0500 Received: from mail-qt0-f196.google.com ([209.85.216.196]:43169 "EHLO mail-qt0-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1763008AbdLSNkB (ORCPT ); Tue, 19 Dec 2017 08:40:01 -0500 X-Google-Smtp-Source: ACJfBouKU64SLQctqYP2upW33jEofiWWA+otwKpT2UzTCc7LFZbOgIq5l0v1uwfktyumIw094AT44g== Date: Tue, 19 Dec 2017 05:39:58 -0800 From: Tejun Heo To: Prateek Sood Cc: peterz@infradead.org, avagin@gmail.com, mingo@kernel.org, linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, sramana@codeaurora.org Subject: Re: [PATCH] cgroup: Fix deadlock in cpu hotplug path Message-ID: <20171219133958.GM3919388@devbig577.frc2.facebook.com> References: <1513668417-26785-1-git-send-email-prsood@codeaurora.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1513668417-26785-1-git-send-email-prsood@codeaurora.org> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 794 Lines: 23 On Tue, Dec 19, 2017 at 12:56:57PM +0530, Prateek Sood wrote: > Deadlock during cgroup migration from cpu hotplug path when a task T is > being moved from source to destination cgroup. ... > Task T inserted a work item in the worklist of cpu0 low priority > worker pool. It is waiting for expedited grace period work item > to execute. This work item will only be executed once kworker/0:0 > complete execution of cpuset_hotplug_workfn(). > > kworker/0:0 ==> Task T ==>kworker/0:0 > > In case of PF_EXITING task being migrated from source to destination > cgroup, migrate next available task in source cgroup. > > Change-Id: I8874fb04479c136cae4dabd5c168c7749df66664 > Signed-off-by: Prateek Sood Applied to cgroup/for-4.15-fixes. Thanks a lot, Prateek. -- tejun