From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934735Ab1ESUnw (ORCPT ); Thu, 19 May 2011 16:43:52 -0400 Received: from hrndva-omtalb.mail.rr.com ([71.74.56.123]:40860 "EHLO hrndva-omtalb.mail.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934077Ab1ESUnv (ORCPT ); Thu, 19 May 2011 16:43:51 -0400 X-Authority-Analysis: v=1.1 cv=ou1QuR4lBR9YeJgEH9ccYmbAdaWqVVq3lOvCKJtMpGM= c=1 sm=0 a=XYJHFtupD_QA:10 a=TwWXrjo8ZJIA:10 a=5SG0PmZfjMsA:10 a=8nJEP1OIZ-IA:10 a=OPBmh+XkhLl+Enan7BmTLg==:17 a=omOdbC7AAAAA:8 a=QyXUC8HyAAAA:8 a=meVymXHHAAAA:8 a=VwQbUJbxAAAA:8 a=W0vUJOdyAAAA:8 a=dObB1cEt5XO7rS6OecIA:9 a=mXLHnUKgPmtDsm5w05sA:7 a=wPNLvfGTeEIA:10 a=x8gzFH9gYPwA:10 a=jeBq3FmKZ4MA:10 a=OPBmh+XkhLl+Enan7BmTLg==:117 X-Cloudmark-Score: 0 X-Originating-IP: 67.242.120.143 Date: Thu, 19 May 2011 16:43:43 -0400 From: Steven Rostedt To: Toralf =?iso-8859-1?Q?F=F6rster?= Cc: richard -rw- weinberger , LKML , user-mode-linux-devel@lists.sourceforge.net Subject: Re: kernel 2.6.39 (user mode linux) crashes (2.6.38 works fine) Message-ID: <20110519204342.GA10792@home.goodmis.org> References: <201105191526.31904.toralf.foerster@gmx.de> <201105192218.18261.toralf.foerster@gmx.de> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <201105192218.18261.toralf.foerster@gmx.de> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, May 19, 2011 at 10:18:16PM +0200, Toralf Förster wrote: > > richard -rw- weinberger wrote at 19:00:35 > > Can you bisect the issue? Is this bug fully reproducable? If not, then you may have had a git bisect good, when it should have been git bisect bad. The futex/plist should not be affecting rwsem. -- Steve > > tfoerste@n22 ~/devel/linux-2.6 $ git bisect bad > 2e12978a9f7a7abd54e8eb9ce70a7718767b8b2c is the first bad commit > commit 2e12978a9f7a7abd54e8eb9ce70a7718767b8b2c > Author: Lai Jiangshan > Date: Wed Dec 22 14:18:50 2010 +0800 > > futex,plist: Pass the real head of the priority list to plist_del() > > Some plist_del()s in kernel/futex.c are passed a faked head of the > priority list. > > It does not fail because the current code does not require the real head > in plist_del(). The current code of plist_del() just uses the head for > checking, > so it will not cause a bad result even when we use a faked head. > > But it is undocumented usage: > > /** > * plist_del - Remove a @node from plist. > * > * @node: &struct plist_node pointer - entry to be removed > * @head: &struct plist_head pointer - list head > */ > > The document says that the @head is the "list head" head of the priority > list. > > In futex code, several places use "plist_del(&q->list, &q->list.plist);", > they pass a fake head. We need to fix them all. > > Thanks to Darren Hart for many suggestions. > > Acked-by: Darren Hart > Signed-off-by: Lai Jiangshan > LKML-Reference: <4D11984A.5030203@cn.fujitsu.com> > Signed-off-by: Steven Rostedt > > :040000 040000 78d47de377f8da1c131007a17ca915fbd13f7ff6 > ffac93205aaf22fda0667d6395c8da7c7bf692e4 M kernel > > -- > MfG/Sincerely > Toralf Förster > pgp finger print: 7B1A 07F4 EC82 0F90 D4C2 8936 872A E508 7DB6 9DA3 > -- > 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/ From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Thu, 19 May 2011 16:43:43 -0400 From: Steven Rostedt Message-ID: <20110519204342.GA10792@home.goodmis.org> References: <201105191526.31904.toralf.foerster@gmx.de> <201105192218.18261.toralf.foerster@gmx.de> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: QUOTED-PRINTABLE In-Reply-To: <201105192218.18261.toralf.foerster@gmx.de> Sender: linux-kernel-owner@vger.kernel.org Subject: Re: kernel 2.6.39 (user mode linux) crashes (2.6.38 works fine) To: Toralf =?iso-8859-1?Q?F=F6rster?= Cc: richard -rw- weinberger , LKML , user-mode-linux-devel@lists.sourceforge.net List-ID: On Thu, May 19, 2011 at 10:18:16PM +0200, Toralf F=F6rster wrote: >=20 > richard -rw- weinberger wrote at 19:00:35 > > Can you bisect the issue? Is this bug fully reproducable? If not, then you may have had a git bisect good, when it should have been git bisect bad. The futex/plist should not be affecting rwsem. -- Steve >=20 > tfoerste@n22 ~/devel/linux-2.6 $ git bisect bad > 2e12978a9f7a7abd54e8eb9ce70a7718767b8b2c is the first bad commit > commit 2e12978a9f7a7abd54e8eb9ce70a7718767b8b2c > Author: Lai Jiangshan > Date: Wed Dec 22 14:18:50 2010 +0800 >=20 > futex,plist: Pass the real head of the priority list to plist_del= () > =20 > Some plist_del()s in kernel/futex.c are passed a faked head of th= e > priority list. > =20 > It does not fail because the current code does not require the re= al head > in plist_del(). The current code of plist_del() just uses the hea= d for=20 > checking, > so it will not cause a bad result even when we use a faked head. > =20 > But it is undocumented usage: > =20 > /** > * plist_del - Remove a @node from plist. > * > * @node: &struct plist_node pointer - entry to be removed > * @head: &struct plist_head pointer - list head > */ > =20 > The document says that the @head is the "list head" head of the p= riority=20 > list. > =20 > In futex code, several places use "plist_del(&q->list, &q->list.p= list);", > they pass a fake head. We need to fix them all. > =20 > Thanks to Darren Hart for many suggestions. > =20 > Acked-by: Darren Hart > Signed-off-by: Lai Jiangshan > LKML-Reference: <4D11984A.5030203@cn.fujitsu.com> > Signed-off-by: Steven Rostedt >=20 > :040000 040000 78d47de377f8da1c131007a17ca915fbd13f7ff6=20 > ffac93205aaf22fda0667d6395c8da7c7bf692e4 M kernel >=20 > --=20 > MfG/Sincerely > Toralf F=F6rster > pgp finger print: 7B1A 07F4 EC82 0F90 D4C2 8936 872A E508 7DB6 9DA3 > -- > To unsubscribe from this list: send the line "unsubscribe linux-kerne= l" 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/