From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752877AbZKDHld (ORCPT ); Wed, 4 Nov 2009 02:41:33 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751567AbZKDHld (ORCPT ); Wed, 4 Nov 2009 02:41:33 -0500 Received: from [95.166.99.235] ([95.166.99.235]:56145 "EHLO kernel.dk" rhost-flags-FAIL-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1751433AbZKDHlc (ORCPT ); Wed, 4 Nov 2009 02:41:32 -0500 Date: Wed, 4 Nov 2009 08:41:37 +0100 From: Jens Axboe To: Andrew Morton Cc: Robert Hancock , linux-kernel , "Rafael J. Wysocki" Subject: Re: 2.6.32-rc4ish: task umount blocked for more than 120 seconds after USB drive removal Message-ID: <20091104074137.GU8742@kernel.dk> References: <4ADE9B79.9090906@gmail.com> <20091103151812.2acc5259.akpm@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20091103151812.2acc5259.akpm@linux-foundation.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Nov 03 2009, Andrew Morton wrote: > On Tue, 20 Oct 2009 23:26:17 -0600 > Robert Hancock wrote: > > > Running a post-2.6.32-rc4 git kernel, and just unmounted a USB drive > > after writing a bunch of data to it, then pulled the plug after I > > thought it had finished unmounting, but apparently it hadn't.. Ran into > > a hung task warning that repeats every 120 seconds, the umount command > > for the drive is stuck in D state. > > > > The full SysRq-T output is shown at the bottom.. any ideas what it's > > waiting for? > > At a guess I'd say the new per-bdi writeback stuff blew up. Is this > still happening in current mainline? It happens in -rc6, it should be fixed in current -git. Robert, can you try and confirm? > It's remarkable how much harder these traces are to read post-wordwrapping. Indeed, I always copy into a new buffer and un-wrap them :/ -- Jens Axboe