Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751405AbaDARW4 (ORCPT ); Tue, 1 Apr 2014 13:22:56 -0400 Received: from mx1.redhat.com ([209.132.183.28]:28599 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751247AbaDARWz (ORCPT ); Tue, 1 Apr 2014 13:22:55 -0400 Date: Tue, 1 Apr 2014 13:22:44 -0400 From: Dave Jones To: "Paul E. McKenney" Cc: Linux Kernel Subject: Re: rcu_prempt stalls / lockup Message-ID: <20140401172244.GA10363@redhat.com> Mail-Followup-To: Dave Jones , "Paul E. McKenney" , Linux Kernel References: <20140331230241.GA30019@redhat.com> <20140331232220.GP4284@linux.vnet.ibm.com> <20140331233552.GB30019@redhat.com> <20140401004801.GQ4284@linux.vnet.ibm.com> <20140401150849.GA14757@redhat.com> <20140401153032.GT4284@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20140401153032.GT4284@linux.vnet.ibm.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Apr 01, 2014 at 08:30:32AM -0700, Paul E. McKenney wrote: > > [14403.765300] INFO: rcu_preempt detected stalls on CPUs/tasks: > > [14403.766405] (detected by 0, t=260067 jiffies, g=449892, c=449891, q=0) > > and on and on.. > > > > so kernel space still works like before, but userspace is locked up. > > Interesting. I suspect that if you reverted the rest of this merge > window's RCU patches, you would get the same result. > > > > If that doesn't work, I will need to put together some diagnostic patches. > > > Starting with the one below. > > > > bugger, I forgot to apply this last night. I'll do it on the next run. > > But let's see what this shows first. [ 1173.923463] INFO: rcu_preempt detected stalls on CPUs/tasks: [ 1173.924457] (detected by 0, t=6502 jiffies, g=47728, c=47727, q=0) [ 1173.925199] INFO: Stall ended before state dump start, gp_kthread state: 0x2 [ 1368.859744] INFO: rcu_preempt detected stalls on CPUs/tasks: [ 1368.860754] (detected by 0, t=26007 jiffies, g=47728, c=47727, q=0) [ 1368.861559] INFO: Stall ended before state dump start, gp_kthread state: 0x2 [ 1563.796416] INFO: rcu_preempt detected stalls on CPUs/tasks: [ 1563.797426] (detected by 0, t=45512 jiffies, g=47728, c=47727, q=0) [ 1563.798293] INFO: Stall ended before state dump start, gp_kthread state: 0x2 [ 1758.733747] INFO: rcu_preempt detected stalls on CPUs/tasks: [ 1758.734725] (detected by 0, t=65017 jiffies, g=47728, c=47727, q=0) [ 1758.735526] INFO: Stall ended before state dump start, gp_kthread state: 0x2 [ 1953.670944] INFO: rcu_preempt detected stalls on CPUs/tasks: [ 1953.671932] (detected by 0, t=84522 jiffies, g=47728, c=47727, q=0) [ 1953.672735] INFO: Stall ended before state dump start, gp_kthread state: 0x2 [ 2148.608132] INFO: rcu_preempt detected stalls on CPUs/tasks: [ 2148.609140] (detected by 0, t=104027 jiffies, g=47728, c=47727, q=0) etc etc. Dave -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/