Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751181AbVKEAMJ (ORCPT ); Fri, 4 Nov 2005 19:12:09 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751184AbVKEAMJ (ORCPT ); Fri, 4 Nov 2005 19:12:09 -0500 Received: from smtp.osdl.org ([65.172.181.4]:23261 "EHLO smtp.osdl.org") by vger.kernel.org with ESMTP id S1751181AbVKEAMI (ORCPT ); Fri, 4 Nov 2005 19:12:08 -0500 Date: Fri, 4 Nov 2005 16:08:51 -0800 From: Andrew Morton To: Adrian Bunk Cc: heiko.carstens@de.ibm.com, linux-kernel@vger.kernel.org, aherrman@de.ibm.com, dm-devel@redhat.com Subject: Re: [PATCH resubmit] do_mount: reduce stack consumption Message-Id: <20051104160851.3a7463ff.akpm@osdl.org> In-Reply-To: <20051104235500.GE5368@stusta.de> References: <20051104105026.GA12476@osiris.boeblingen.de.ibm.com> <20051104084829.714c5dbb.akpm@osdl.org> <20051104212742.GC9222@osiris.ibm.com> <20051104235500.GE5368@stusta.de> X-Mailer: Sylpheed version 1.0.0 (GTK+ 1.2.10; i386-vine-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2104 Lines: 45 Adrian Bunk wrote: > > On Fri, Nov 04, 2005 at 10:27:42PM +0100, Heiko Carstens wrote: > > > > See original stack back trace below and Andreas' patch and analysis > > > > here: > > > > http://www.ussg.iu.edu/hypermail/linux/kernel/0410.3/1844.html > > > > I probably should add that with "original" stack back trace a trace of > > a 2.6.10 kernel was meant, if that wasn't clear, but the DM code is > > still the same in 2.6.14. > > > > > > <4>Call Trace: > > ... > > > > <4> [<0000000010831380>] __map_bio+0x70/0x160 [dm_mod] > > > > <4> [<000000001083173e>] __split_bio+0x1e6/0x538 [dm_mod] > > > > <4> [<0000000010831ba8>] dm_request+0x118/0x25c [dm_mod] > > > > <4> [<0000000000241074>] generic_make_request+0xf0/0x21c > > > > <4> [<0000000010831380>] __map_bio+0x70/0x160 [dm_mod] > > > > <4> [<000000001083173e>] __split_bio+0x1e6/0x538 [dm_mod] > > > > <4> [<0000000010831ba8>] dm_request+0x118/0x25c [dm_mod] > > > > <4> [<0000000000241074>] generic_make_request+0xf0/0x21c > > > > <4> [<0000000010831380>] __map_bio+0x70/0x160 [dm_mod] > > > > <4> [<000000001083173e>] __split_bio+0x1e6/0x538 [dm_mod] > > > > <4> [<0000000010831ba8>] dm_request+0x118/0x25c [dm_mod] > > > > <4> [<0000000000241074>] generic_make_request+0xf0/0x21c > > ... > > > > This part of the call trace is actually good for >1500 bytes of stack > > usage and is what kills us and should be fixed. > > I'm surprised that there are no other bug reports regarding DM and > > stack overflow with 4k stacks. > >... > > There were some reports of dm+xfs overflows with 4k stacks on i386. > > The xfs side was sorted out, but I son't know the state of the dm part. > The state is Very Bad, IMO. At the very least, DM should struggle to the utmost to reduce the stack utilisation around that recursion point. - 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/