From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Carlos O'Donell" Subject: Re: futex wait failure Date: Mon, 22 Mar 2010 10:26:17 -0400 Message-ID: <119aab441003220726q68e2ff6cwfce105f5cf068ab8@mail.gmail.com> References: <20100307171207.GA22856@hiauly1.hia.nrc.ca> <20100307203230.CAC964E77@hiauly1.hia.nrc.ca> <20100311032049.GA14312@hiauly1.hia.nrc.ca> <20100311135418.GA22698@bombadil.infradead.org> <20100311224044.GA18789@hiauly1.hia.nrc.ca> <20100313020647.GA26384@hiauly1.hia.nrc.ca> <20100315011024.GA7309@hiauly1.hia.nrc.ca> <119aab441003160449n11cf5272qb9d15fa97625dd7d@mail.gmail.com> <20100321181935.GA19525@hiauly1.hia.nrc.ca> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Cc: Kyle McMartin , deller@gmx.de, linux-parisc@vger.kernel.org To: John David Anglin Return-path: In-Reply-To: <20100321181935.GA19525@hiauly1.hia.nrc.ca> List-ID: List-Id: linux-parisc.vger.kernel.org On Sun, Mar 21, 2010 at 2:19 PM, John David Anglin wrote: > I added an illegal instruction abort to the child. =A0In this case, > the thread_run loop counter was 48085 when the page was copied and > the before value was zero. > > One thought that has crossed my mind is that the memory pages allocat= ed > for the stack region used by the thread are somehow getting interchan= ged > between parent and child by the fork operation. =A0This happens fairl= y > late as both the parent and thread are executing post fork at the tim= e > this happens. =A0Possibly, this is part of the bug. > > I have looked at entry.S and pacache.S quite a bit and it's not obvio= us > how this could happen, although I must admit to not fully understandi= ng > the tmp alias code. =A0I tend to think the bug is in the core mm code= =2E > > I see a few cleanups to entry.S. =A0We didn't kill the misnamed macro= s > (DEP, DEPI and EXTR) for example. =A0But I don't think these are the = problem. Dave, Thank you for another test case. I agree, I also think the bug is in the core mm code, which I am also trying to review and understand. I haven't been able to make much progress in this area though. I'll keep you updated when I spot something I think is wrong. Cheers, Carlos. -- To unsubscribe from this list: send the line "unsubscribe linux-parisc"= in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html