From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peter Zijlstra Date: Wed, 22 Dec 2010 17:25:20 +0000 Subject: Re: [PATCH] avoid race condition in pick_next_task_fair in Message-Id: <1293038720.2170.167.camel@laptop> List-Id: References: <20101219020313.GJ31750@genesis.frugalware.org> <20101222002248.GP10557@genesis.frugalware.org> <1293006589.2170.41.camel@laptop> <1293007311.11370.172.camel@marge.simson.net> <1293008842.2170.70.camel@laptop> <20101222133154.GS10557@genesis.frugalware.org> <1293026422.2170.136.camel@laptop> <1293027112.2170.140.camel@laptop> <20101222151434.GW10557@genesis.frugalware.org> <1293037718.2170.155.camel@laptop> <20101222171655.GB25611@elte.hu> In-Reply-To: <20101222171655.GB25611@elte.hu> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Ingo Molnar Cc: Miklos Vajna , Mike Galbraith , shenghui , kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org, Greg KH On Wed, 2010-12-22 at 18:16 +0100, Ingo Molnar wrote: > * Peter Zijlstra wrote: > > > On Wed, 2010-12-22 at 16:14 +0100, Miklos Vajna wrote: > > > kernel-build is a git build using the config I already sent and after a > > > 'git checkout v2.6.36'. I can try to build master as well, so far what I > > > saw is that the bug occurs there as well, but less frequently, so maybe > > > that's a bit harder to debug. > > > > Right, so I've got v2.6.36 exploding, current -git and -tip won't > > explode for me, tried both about 20 times. So I'll try and figure out > > wth makes .36 explode and then see if further kernel still suffer that > > problem. > > Does it explode if you change some of the CONFIG_CC flags, such as > CONFIG_CC_OPTIMIZE_FOR_SIZE? I.e. is the crash dependent on the precise kernel image > layout perhaps? If it's sensitive to that then this might keep you from chasing > shadows ... I've since changed the .config slightly (enabled frame pointers, added debug info, enabled the function tracer) and its still exploding. Also, I suspect Miklos and me have different gcc versions. So I suspect its really something weird, I just can't really make sense of it yet.