Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262110AbVCZO3L (ORCPT ); Sat, 26 Mar 2005 09:29:11 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262113AbVCZO3L (ORCPT ); Sat, 26 Mar 2005 09:29:11 -0500 Received: from pentafluge.infradead.org ([213.146.154.40]:16297 "EHLO pentafluge.infradead.org") by vger.kernel.org with ESMTP id S262110AbVCZO3E (ORCPT ); Sat, 26 Mar 2005 09:29:04 -0500 Subject: Re: 2.6.12-rc1 breaks dosemu From: Arjan van de Ven To: Arnd Bergmann Cc: Bart Oldeman , Adrian Bunk , linux-kernel@vger.kernel.org, linux-msdos@vger.kernel.org, Ingo Molnar In-Reply-To: <200503261449.46219.arnd@arndb.de> References: <20050320021141.GA4449@stusta.de> <1111824629.6293.19.camel@laptopd505.fenrus.org> <200503261449.46219.arnd@arndb.de> Content-Type: text/plain; charset=UTF-8 Date: Sat, 26 Mar 2005 15:28:56 +0100 Message-Id: <1111847336.8042.26.camel@laptopd505.fenrus.org> Mime-Version: 1.0 X-Mailer: Evolution 2.0.4 (2.0.4-2) Content-Transfer-Encoding: 8bit X-Spam-Score: 3.7 (+++) X-Spam-Report: SpamAssassin version 2.63 on pentafluge.infradead.org summary: Content analysis details: (3.7 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- 1.1 RCVD_IN_DSBL RBL: Received via a relay in list.dsbl.org [] 2.5 RCVD_IN_DYNABLOCK RBL: Sent directly from dynamic IP address [80.57.133.107 listed in dnsbl.sorbs.net] 0.1 RCVD_IN_SORBS RBL: SORBS: sender is listed in SORBS [80.57.133.107 listed in dnsbl.sorbs.net] X-SRS-Rewrite: SMTP reverse-path rewritten from by pentafluge.infradead.org See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1369 Lines: 31 On Sat, 2005-03-26 at 14:49 +0100, Arnd Bergmann wrote: > On Sünnavend 26 März 2005 09:18, Bart Oldeman wrote: > > On Sat, 26 Mar 2005, Arjan van de Ven wrote: > > > > > > eip: 0x000069ee esp: 0xbfdbffcc eflags: 0x00010246 > > > > > > hmm interesting. Can you check if at the time of the crash, the esp is > > > actually inside the stack vma? If it's not, I wonder what dosemu does to > > > get its stack pointer outside the vma... (and on which side of the vma > > > it is) > > The esp value is always slightly below the stack vma and above ld.so. > Running it a few times gives > > stack VMA crash esp > bfc8f000-bfca4000 bfc5ffcc the esp is 0x2F034/192564 bytes below the stack vma. That is a lot! I vaguely remember linux having a limit to how much below the stack vma it will allow accesses to auto-grow the stack, but I forgot what that limit actually was. I wonder if dosemu is somehow getting away with assuming a certain alignment by accident and then being inside the kernel grow limit, while with randomisation the alignment is only 4Kb and somehow a bigger-than-expected auto-grow is needed. - 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/