Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753697Ab0BOCi7 (ORCPT ); Sun, 14 Feb 2010 21:38:59 -0500 Received: from fgwmail5.fujitsu.co.jp ([192.51.44.35]:51025 "EHLO fgwmail5.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753422Ab0BOCi6 (ORCPT ); Sun, 14 Feb 2010 21:38:58 -0500 X-SecurityPolicyCheck-FJ: OK by FujitsuOutboundMailChecker v1.3.1 From: KOSAKI Motohiro To: Michael Neuling Subject: Re: 2.6.33-rc8 breaks UML with Restrict initial stack space expansion to rlimit Cc: kosaki.motohiro@jp.fujitsu.com, Jouni Malinen , linux-kernel@vger.kernel.org In-Reply-To: <9296.1266185019@neuling.org> References: <20100214164023.GA2726@jm.kir.nu> <9296.1266185019@neuling.org> Message-Id: <20100215113751.7275.A69D9226@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-Mailer: Becky! ver. 2.50.07 [ja] Date: Mon, 15 Feb 2010 11:38:52 +0900 (JST) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3700 Lines: 95 > > > In message <20100214164023.GA2726@jm.kir.nu> you wrote: > > It looks like the commit 803bf5ec259941936262d10ecc84511b76a20921 > > (fs/exec.c: restrict initial stack space expansion to rlimit) broke my > > user mode Linux setup by somehow preventing system setup from running > > properly (or killing some processes that try to mount things, etc.). > > This commit turned up as the reason based on git bisect and reverting it > > fixes my UML test setup (Ubuntu 9.10 on both host and in UML and AMD64 > > arch for both). I have no idea what exactly would be the main cause for > > this issue, but this looks like a somewhat unfortunately timed > > regression in 2.6.33-rc8. > > > > The failed run shows like this (with current linux-2.6.git): > > > > ... > > EXT3-fs (ubda): mounted filesystem with writeback data mode > > VFS: Mounted root (ext3 filesystem) readonly on device 98:0. > > IRQ 3/console-write: IRQF_DISABLED is not guaranteed on shared IRQs > > IRQ 2/console: IRQF_DISABLED is not guaranteed on shared IRQs > > IRQ 10/winch: IRQF_DISABLED is not guaranteed on shared IRQs > > IRQ 10/winch: IRQF_DISABLED is not guaranteed on shared IRQs > > mountall: mount /sys/kernel/debug [218] killed by KILL signal > > mountall: Filesystem could not be mounted: /sys/kernel/debug > > mountall: mount /dev [219] killed by KILL signal > > mountall: Filesystem could not be mounted: /dev > > mountall: mount /tmp [220] killed by KILL signal > > mountall: Filesystem could not be mounted: /tmp > > mountall: mount /var/lock [222] killed by KILL signal > > mountall: Filesystem could not be mounted: /var/lock > > ... Wow. It seems very strange. Usually stack overflow makes SIGSEGV, not SIGKILL. plus, In my environment (x86_64 non-uml), mount command doesn't use the stack so much. % /usr/bin/time --format="mem %M" ls /usr/bin/time --format="mem %M" ls GPATH INSTALL README configure fdisk lib misc-utils schedutils mem 3232 % sudo /usr/bin/time --format="mem %M" mount -a sudo /usr/bin/time --format="mem %M" mount -a mem 2992 Hmmm... I have no idea. > > > > > > With 803bf5ec reverted, UML comes up and the output looks like this: > > > > ... > > EXT3-fs (ubda): mounted filesystem with writeback data mode > > VFS: Mounted root (ext3 filesystem) readonly on device 98:0. > > IRQ 3/console-write: IRQF_DISABLED is not guaranteed on shared IRQs > > IRQ 2/console: IRQF_DISABLED is not guaranteed on shared IRQs > > IRQ 10/winch: IRQF_DISABLED is not guaranteed on shared IRQs > > IRQ 10/winch: IRQF_DISABLED is not guaranteed on shared IRQs > > init: procps main process (226) terminated with status 255 > > fsck from util-linux-ng 2.16 > > ... > > Crud, the "killed" is definitely something this patch could cause. > > I'm not familiar with UML. Is this the guest and the host booting rc8, > or just the host? Does UML use stack protection at all? > > Can you try booting the guest to init=/bin/sh and try running some tests > to see what you can set 'ulimit -s' to and still be able to run a simple > command like '/bin/ls'? > > Mikey > > > > > -- > > Jouni Malinen PGP id EFC895FA > > > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/