From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933958Ab2AKUXb (ORCPT ); Wed, 11 Jan 2012 15:23:31 -0500 Received: from lo.gmane.org ([80.91.229.12]:47442 "EHLO lo.gmane.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933921Ab2AKUXL (ORCPT ); Wed, 11 Jan 2012 15:23:11 -0500 X-Injected-Via-Gmane: http://gmane.org/ To: linux-kernel@vger.kernel.org From: Mantas Subject: Re: 3.2rc7 rcu_preempt stalls and tasks blocked. Date: Wed, 11 Jan 2012 22:22:40 +0200 Message-ID: References: Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Complaints-To: usenet@dough.gmane.org X-Gmane-NNTP-Posting-Host: 78-60-211-195.static.zebra.lt User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:9.0) Gecko/20111224 Thunderbird/9.0.1 In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2011-12-24 16:09, Jonathan Hudson wrote: > Ever since 3.1, I've been experiencing rcu_preempt stalls, tasks > blocked and subsequent lock ups on an eeepc 901. Judging by the thread > on the Arch forums, this is not > an uncommon experience. Can confirm on ASUS K52JT, using 3.2 (Arch Linux) and various git builds starting around 3.2-rc6/7. Appears to be caused by heavier wireless network activity (ath9k, Atheros AR9285, open network, IPv4 & IPv6), such as BitTorrent -- although not by ordinary HTTP or such. Other posts in the Arch bug report say having ipv6 loaded/enabled is causing the problem. During the lockup, accessing certain files in /proc (can't remember all, but /proc/*/mounts and /proc/*/cgroup included) causes the process to hang; same when running `ip`, `iwconfig` and related tools. Often (but not always), killing NetworkManager makes everything work again. Hoping for a fix someday. -- Mantas M.