Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753586AbdHQVaJ (ORCPT ); Thu, 17 Aug 2017 17:30:09 -0400 Received: from mail.kernel.org ([198.145.29.99]:48648 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753005AbdHQVaH (ORCPT ); Thu, 17 Aug 2017 17:30:07 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1225B2170E Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=goodmis.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=rostedt@goodmis.org Date: Thu, 17 Aug 2017 17:30:04 -0400 From: Steven Rostedt To: Waiman Long Cc: Jens Axboe , Jeff Layton , "J. Bruce Fields" , Ingo Molnar , linux-kernel@vger.kernel.org, linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org Subject: Re: [PATCH v2] blktrace: Fix potentail deadlock between delete & sysfs ops Message-ID: <20170817173004.263d2891@gandalf.local.home> In-Reply-To: <20170817171007.1ab33b8f@gandalf.local.home> References: <1502916040-18067-1-git-send-email-longman@redhat.com> <20170817093444.3276f7ab@gandalf.local.home> <20170817171007.1ab33b8f@gandalf.local.home> X-Mailer: Claws Mail 3.14.0 (GTK+ 2.24.31; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 546 Lines: 15 On Thu, 17 Aug 2017 17:10:07 -0400 Steven Rostedt wrote: > Instead of playing games with taking the lock, the only way this race > is hit, is if the partition is being deleted and the sysfs attribute is > being read at the same time, correct? In that case, just return > -ENODEV, and be done with it. Nevermind that wont work. Too bad there's not a mutex_lock_timeout() that we could use in a loop. It would solve the issue of forward progress with RT tasks, and will break after a timeout in case of deadlock. -- Steve