Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752322AbdHCD4M (ORCPT ); Wed, 2 Aug 2017 23:56:12 -0400 Received: from mail-pf0-f177.google.com ([209.85.192.177]:36793 "EHLO mail-pf0-f177.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752294AbdHCD4K (ORCPT ); Wed, 2 Aug 2017 23:56:10 -0400 Subject: Re: rcu_sched stall while waiting in csd_lock_wait() To: Peter Zijlstra Cc: "Paul E. McKenney" , Will Deacon , open list , linux-arm-kernel References: <20170802081437.24skpbdglcymd5em@hirez.programming.kicks-ass.net> From: Pratyush Anand Message-ID: <00171457-416c-94c6-21c7-28817e7367ab@redhat.com> Date: Thu, 3 Aug 2017 09:26:06 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.2.1 MIME-Version: 1.0 In-Reply-To: <20170802081437.24skpbdglcymd5em@hirez.programming.kicks-ass.net> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 769 Lines: 24 Hi Peter, On Wednesday 02 August 2017 01:44 PM, Peter Zijlstra wrote: > On Wed, Aug 02, 2017 at 09:01:19AM +0530, Pratyush Anand wrote: >> Hi, >> >> I am observing following rcu_sched stall while executing `perf record -a -- >> sleep 1` with one of the arm64 platform. It looks like that stalled cpu was >> waiting in csd_lock_wait() from where it never came out,and so the stall. >> Any help/pointer for further debugging would be very helpful. Problem also >> reproduced with 4.13.0-rc3. > > I'm sitting on this patch: > > https://git.kernel.org/pub/scm/linux/kernel/git/peterz/queue.git/commit/?h=locking/core&id=15377ef4fe0c86eb7fa1099575b2e86357d99e42 > > please give that a spin. Thanks for the pointer. Tried, but it did not help. -- Regards Pratyush