This message generated a parse failure. Raw output follows here. Please use 'back' to navigate. From devnull@lkml.org Sat Jun 1 03:28:16 2024 Delivery-date: Fri, 12 May 2006 16:08:18 +0200 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932092AbWELOHw (ORCPT ); Fri, 12 May 2006 10:07:52 -0400 Received: from spirit.analogic.com ([204.178.40.4]:58129 "EHLO spirit.analogic.com") by vger.kernel.org with ESMTP id S932085AbWELOHv convert rfc822-to-8bit (ORCPT ); Fri, 12 May 2006 10:07:51 -0400 Received: from chaos.analogic.com ([10.112.50.11]) by phoenix.analogic.com with Microsoft SMTPSVC(6.0.3790.211); Fri, 12 May 2006 10:07:51 -0400 Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7BIT Received: from chaos.analogic.com (localhost [127.0.0.1]) by chaos.analogic.com (8.12.11/8.12.11) with ESMTP id k4CE7pNZ009044; Fri, 12 May 2006 10:07:51 -0400 X-MimeOLE: Produced By Microsoft Exchange V6.5.7226.0 Received: (from linux-os@localhost) by chaos.analogic.com (8.12.11/8.12.11/Submit) id k4CE7oO6009043; Fri, 12 May 2006 10:07:50 -0400 X-OriginalArrivalTime: 12 May 2006 14:07:51.0157 (UTC) FILETIME=[74990A50:01C675CD] content-class: urn:content-classes:message Subject: Re: Segfault on the i386 enter instruction Date: Fri, 12 May 2006 10:07:50 -0400 Message-Id: In-Reply-To: <20060512131654.GB2994@duch.mimuw.edu.pl> X-MS-Has-Attach: X-MS-TNEF-Correlator: Thread-Topic: Segfault on the i386 enter instruction Thread-Index: AcZ1zXSgzG6/PoLNS9+nFYQ8EGtOCg== References: <20060512131654.GB2994@duch.mimuw.edu.pl> From: "linux-os \(Dick Johnson\)" To: "Tomasz Malesinski" Cc: Reply-To: "linux-os \(Dick Johnson\)" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 12 May 2006, Tomasz Malesinski wrote: > The code attached below segfaults on the enter instruction. It works > when a stack frame is created by the three commented out > instructions and also when the first operand of the enter instruction > is small (less than about 6500 on my system). > > AFAIK, the only difference between creating a stack frame with the > enter instruction or push/mov/sub is that enter checks if the new > value of esp is inside the stack segment limit. > > I tested it on a vanilla kernel 2.4.26 on Intel Celeron and also on > probably non-vanilla 2.6.16.13 running on 3 dual core AMD Opteron, > quite busy, server. It is working in 32-bit mode. Interestingly, on > the second machine sometimes the program worked correctly. > > I am not subscribed to the list. Please cc replies to me. > > > .file "a.c" > .version "01.01" > gcc2_compiled.: > .section .rodata > .LC0: > .string "asdf\n" > .text > .align 4 > .globl main > .type main,@function > main: > enter $10008, $0 > # pushl %ebp > # movl %esp,%ebp > # subl $10008,%esp > addl $-12,%esp ^^^^^^^^^^^^^^____________ WTF adding a negative number is subtracting that positive value. You just subtracted 0xfffffff3 (on a 32-bit machine) from the stack pointer. It damn-well better seg-fault! > pushl $.LC0 > call printf > addl $16,%esp > .L2: > leave > ret > .Lfe1: > .size main,.Lfe1-main > .ident "GCC: (GNU) 2.95.4 20011002 (Debian prerelease)" > > -- > Tomek Malesinski > - > 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/ > Cheers, Dick Johnson Penguin : Linux version 2.6.16.4 on an i686 machine (5592.89 BogoMips). New book: http://www.lymanschool.com _  **************************************************************** The information transmitted in this message is confidential and may be privileged. Any review, retransmission, dissemination, or other use of this information by persons or entities other than the intended recipient is prohibited. If you are not the intended recipient, please notify Analogic Corporation immediately - by replying to this message or by sending an email to DeliveryErrors@analogic.com - and destroy all copies of this information, including any attachments, without reading or disclosing them. Thank you. - 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/