From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756245AbbJALfx (ORCPT ); Thu, 1 Oct 2015 07:35:53 -0400 Received: from dresden.studentenwerk.mhn.de ([141.84.225.229]:48462 "EHLO email.studentenwerk.mhn.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755373AbbJALfu convert rfc822-to-8bit (ORCPT ); Thu, 1 Oct 2015 07:35:50 -0400 X-Greylist: delayed 398 seconds by postgrey-1.27 at vger.kernel.org; Thu, 01 Oct 2015 07:35:49 EDT From: Wolfgang Walter To: Andre Tomt Cc: Julian Anastasov , Greg Kroah-Hartman , linux-kernel@vger.kernel.org, "David S. Miller" , stable@vger.kernel.org, "Eric W. Biederman" , Stephen Hemminger , holger.hoffstaette@googlemail.com, Linux Netdev List Subject: kernel 4.1.9: networking hangs with rcu_preempt self-detected stall, 4.1.8 works; was: Re: [PATCH 4.1 125/159] net: call rcu_read_lock early in process_backlog Date: Thu, 01 Oct 2015 13:29:09 +0200 Message-ID: <3770693.fDE1nljnWm@stwm.de> User-Agent: KMail/4.14.2 (Linux/3.16.0-34-generic; KDE/4.14.2; i686; ; ) In-Reply-To: <560A6C8B.7080105@tomt.net> References: <20150926205313.363686083@linuxfoundation.org> <560A661C.7000406@tomt.net> <560A6C8B.7080105@tomt.net> MIME-Version: 1.0 Content-Transfer-Encoding: 8BIT Content-Type: text/plain; charset="iso-8859-1" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Am Dienstag, 29. September 2015, 12:48:43 schrieb Andre Tomt: > On 29. sep. 2015 12:21, Andre Tomt wrote: > > Meanwhile I'll revert both the mentioned net patches and see how it goes. > > So that blew up as well, meaning it's not any of these two patches: > [PATCH 4.1 124/159] net: do not process device backlog during unregistration > [PATCH 4.1 125/159] net: call rcu_read_lock early in process_backlog > > I'll be offline for a half+ day, I'll look into bisecting when back if > nobody has figured it out by then. > -- > To unsubscribe from this list: send the line "unsubscribe stable" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html We see these rcu hangs with 4.1.9 on one of our routers, too. 4.1.8 runs fine. The output I got the last time was: [ 6488.174578] igb 000:06:00.1 eth3: Reset adapter [ 6497.350183] INFO: rcu_preempt self-detected stall on CPU { 3} (t=6301 jiffies g=383330 c=383329 q=1323) [ 6497.350229] rcu_preempt kthread starved for 6007 jiffies! [ 6560.311093] INFO: rcu_preempt self-detected stall on CPU { 3} (t=25205 jiffies g=383330 c=383329 q=4479) [ 6560.311140] rcu_preempt kthread starved for 24911 jiffies! [ 6623.272005] INFO: rcu_preempt self-detected stall on CPU { 3} (t=44109 jiffies g=383330 c=383329 q=7107) [ 6623.272049] rcu_preempt kthread starved for 43815 jiffies! [ 6633.053892] igb 000:06:00.0 eth2: Reset adapter [ 6633.053892] rcu_preempt kthread starved for 62719 jiffies! [ 6486.232914] INFO: rcu_preempt self-detected stall on CPU { 3} (t=63013 jiffies g=383330 c=383329 q=8487) [ 6486.233204] rcu_preempt kthread starved for 6007 jiffies! All other hangs basically were the same, the cpu varies though. After that the router completely hangs: networking stops working and we need to restart it. Regards, -- Wolfgang Walter Studentenwerk München Anstalt des öffentlichen Rechts