From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934471AbcIVLJd (ORCPT ); Thu, 22 Sep 2016 07:09:33 -0400 Received: from mail-wm0-f51.google.com ([74.125.82.51]:34903 "EHLO mail-wm0-f51.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934129AbcIVLJ2 (ORCPT ); Thu, 22 Sep 2016 07:09:28 -0400 Date: Thu, 22 Sep 2016 13:09:25 +0200 From: Michal Hocko To: Mike Galbraith Cc: LKML , strace-devel@lists.sourceforge.net, Oleg Nesterov , Aleksa Sarai Subject: Re: strace lockup when tracing exec in go Message-ID: <20160922110925.GE11875@dhcp22.suse.cz> References: <20160921152946.GA24210@dhcp22.suse.cz> <1474517702.4851.21.camel@gmail.com> <20160922080126.GA11875@dhcp22.suse.cz> <20160922083602.GB11875@dhcp22.suse.cz> <1474537209.5022.8.camel@gmail.com> <20160922095303.GD11875@dhcp22.suse.cz> <1474538945.5022.20.camel@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1474538945.5022.20.camel@gmail.com> User-Agent: Mutt/1.6.0 (2016-04-01) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu 22-09-16 12:09:05, Mike Galbraith wrote: > On Thu, 2016-09-22 at 11:53 +0200, Michal Hocko wrote: > > On Thu 22-09-16 11:40:09, Mike Galbraith wrote: > > > > This patch doesn't help, nor does the previous patch... but with both > > > applied, all is well. All you have to do now is figure out why :) > > > > Ohh, I should be more explicit, this needs the mm_access part as well. > > Sorry for not being clear enough. So the full change is > > Ah. That was gonna happen after lunch, but since you already know it > works, I can get back to un-b0rking one of my trees. Yeah, it should work. The testcase is running in a loop for more than hour already and everything seems to be ok. Now the question is whether the fix is really correct which is something for Oleg. Also I think there is at least one more issue lurking there. Without or without the patch I can make tracer get stuck in do_wait waiting for task which doesn't seem to be alive anymore. I will report it separately after this one gets resolved to not pull more confusion in. Anyway, thanks for your time Mike! -- Michal Hocko SUSE Labs