From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from sc8-sf-mx1-b.sourceforge.net ([10.3.1.91] helo=mail.sourceforge.net) by sc8-sf-list1-new.sourceforge.net with esmtp (Exim 4.43) id 1KKaiD-00074e-22 for user-mode-linux-devel@lists.sourceforge.net; Sun, 20 Jul 2008 08:20:37 -0700 Received: from static-220-247-10-204.b-man.svips.gol.ne.jp ([220.247.10.204] helo=tadamune.kami.home) by mail.sourceforge.net with esmtps (TLSv1:AES256-SHA:256) (Exim 4.44) id 1KKai9-0008MY-LB for user-mode-linux-devel@lists.sourceforge.net; Sun, 20 Jul 2008 08:20:37 -0700 Date: Mon, 21 Jul 2008 00:20:22 +0900 From: Mattia Dongili Message-ID: <20080720152022.GE1520@inferi.kami.home> References: <5df78e1d0807030053x8a9bfabo582ea78e74b2c65b@mail.gmail.com> <20080703135639.GA8262@c2.user-mode-linux.org> <5df78e1d0807031806s74c13c84idadc62c1d1e0e93b@mail.gmail.com> <5df78e1d0807091925q64c0121fk3d33c37df8d80d18@mail.gmail.com> <20080710170210.GB18429@c2.user-mode-linux.org> <5df78e1d0807140206m43291128t32f1489177ad6e3d@mail.gmail.com> <20080714144612.GA5751@c2.user-mode-linux.org> <5df78e1d0807160252j1b610c41la1a2f5092ae04be7@mail.gmail.com> <5df78e1d0807162155t594936c9qe5bc1616fae97f77@mail.gmail.com> <20080718205342.GE13572@c2.user-mode-linux.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20080718205342.GE13572@c2.user-mode-linux.org> Subject: Re: [uml-devel] 2.6.25 uml kernel crashes when it calls down() on a semaphore with zero counter List-Id: The user-mode Linux development list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: user-mode-linux-devel-bounces@lists.sourceforge.net Errors-To: user-mode-linux-devel-bounces@lists.sourceforge.net To: Jeff Dike Cc: user-mode-linux-devel@lists.sourceforge.net, Jiaying Zhang On Fri, Jul 18, 2008 at 04:53:42PM -0400, Jeff Dike wrote: > On Thu, Jul 17, 2008 at 12:55:09PM +0800, Jiaying Zhang wrote: > > The patch below solves the 2.6.25 uml crash problem for me. Looks like the > > problem should be away in 2.6.26 kernel because down_interruptible has > > changed to the C code since 2.6.26. But I got kernel panic while booting > > the 2.6.26 kernel :(. > > > > --- linux-2.6.25.4/lib/semaphore-sleepers.c 2008-05-15 > > 23:00:12.000000000 +0800 > > +++ linux-2.6.25.4-new/lib/semaphore-sleepers.c 2008-07-17 > > 12:20:47.000000000 +0800 > > @@ -48,12 +48,12 @@ > > * we cannot lose wakeup events. > > */ > > > > -void __up(struct semaphore *sem) > > +asmregparm void __up(struct semaphore *sem) > > { > > wake_up(&sem->wait); > > } > > You continue to ignore a few important facts: > > 1 - There are a ton of semaphores in UML > 2 - They all work, except for yours > Therefore, a patch which changes all semphores across all > architectures for which asmregparam has meaning can't possibly be the > correct fix. > > However, you might have treated this as an important clue, and looked > at whether your broken semaphore has a different set of declarations > in force than those in the rest of the kernel. Jeff, it's not entirely clear to me why, but that patch fixes a segfault that I experience when booting uml 2.6.25 built with gcc-4.3 on a 2.6.25 host (I also applied your ICE workaround patch). I'm booting a debian sid image that I usually run before uploading the new uml package in debian. I've got no fancy modules written by me and the segfault is 100% reproducible with that debian image (a different image -a gentoo- doesn't crash). I'll provide more info tomorrow, I'll try to further trace the crash with gdb. cheers -- mattia :wq! ------------------------------------------------------------------------- This SF.Net email is sponsored by the Moblin Your Move Developer's challenge Build the coolest Linux based applications with Moblin SDK & win great prizes Grand prize is a trip for two to an Open Source event anywhere in the world http://moblin-contest.org/redirect.php?banner_id=100&url=/ _______________________________________________ User-mode-linux-devel mailing list User-mode-linux-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel