From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755249AbZBBOxZ (ORCPT ); Mon, 2 Feb 2009 09:53:25 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751797AbZBBOxQ (ORCPT ); Mon, 2 Feb 2009 09:53:16 -0500 Received: from cam-admin0.cambridge.arm.com ([193.131.176.58]:60187 "EHLO cam-admin0.cambridge.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751393AbZBBOxP (ORCPT ); Mon, 2 Feb 2009 09:53:15 -0500 To: Alexander Beregalov Cc: "linux-next\@vger.kernel.org" , LKML Subject: Re: next-20090202: task kmemleak:763 blocked for more than 120 seconds. References: From: Catalin Marinas Date: Mon, 02 Feb 2009 14:53:05 +0000 In-Reply-To: (Alexander Beregalov's message of "Mon\, 2 Feb 2009 14\:27\:28 +0300") Message-ID: User-Agent: Gnus/5.11 (Gnus v5.11) Emacs/22.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-OriginalArrivalTime: 02 Feb 2009 14:53:11.0024 (UTC) FILETIME=[F79C8F00:01C98545] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Alexander Beregalov wrote: > It seems it is blocked forever. Scanning the full memory may take a lot of time, depending on the amount of RAM and the number of objects allocated. It is not unlikely to take more than 120 seconds on some loaded systems. However, it should call schedule() periodically to let other tasks run. Is your system unresponsive during this? > [ 1704.619898] INFO: task kmemleak:763 blocked for more than 120 seconds. > [ 1704.697951] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" > disables this message. > [ 1704.791613] kmemleak D 0000000000000001 6008 763 2 [...] > [ 1706.246334] no locks held by kmemleak/763. It looks like the kmemleak thread is in the TASK_UNINTERUPTIBLE state. This happens when it calls schedule_timeout_uninterruptible() to sleep between scans. It probably took more than 120 to scan the memory and hence the report. It doesn't look like a problem, only that the watchdog thread checks for uninterruptible tasks. I can try to make it sleep with TASK_INTERRUPTIBLE to avoid the message. Thanks. -- Catalin