From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932198AbWGRS1j (ORCPT ); Tue, 18 Jul 2006 14:27:39 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932344AbWGRS1i (ORCPT ); Tue, 18 Jul 2006 14:27:38 -0400 Received: from liaag2af.mx.compuserve.com ([149.174.40.157]:63913 "EHLO liaag2af.mx.compuserve.com") by vger.kernel.org with ESMTP id S932198AbWGRS1i (ORCPT ); Tue, 18 Jul 2006 14:27:38 -0400 Date: Tue, 18 Jul 2006 14:22:36 -0400 From: Chuck Ebbert <76306.1226@compuserve.com> Subject: [patch] i386: show_registers(): try harder to print failing code To: linux-kernel Cc: Andrew Morton , Linus Torvalds , Andi Kleen Message-ID: <200607181425_MC3-1-C556-424A@compuserve.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org show_registers() tries to dump failing code starting 43 bytes before the offending instruction, but this address can be bad, for example in a device driver where the failing instruction is less than 43 bytes from the start of the driver's code. When that happens, try to dump code starting at the failing instruction instead of printing no code at all. Signed-off-by: Chuck Ebbert <76306.1226@compuserve.com> --- 2.6.18-rc1-32.orig/arch/i386/kernel/traps.c +++ 2.6.18-rc1-32/arch/i386/kernel/traps.c @@ -307,6 +307,8 @@ void show_registers(struct pt_regs *regs */ if (in_kernel) { u8 __user *eip; + int code_bytes = 64; + unsigned char c; printk("\n" KERN_EMERG "Stack: "); show_stack_log_lvl(NULL, regs, (unsigned long *)esp, KERN_EMERG); @@ -314,9 +316,12 @@ void show_registers(struct pt_regs *regs printk(KERN_EMERG "Code: "); eip = (u8 __user *)regs->eip - 43; - for (i = 0; i < 64; i++, eip++) { - unsigned char c; - + if (eip < (u8 __user *)PAGE_OFFSET || __get_user(c, eip)) { + /* try starting at EIP */ + eip = (u8 __user *)regs->eip; + code_bytes = 32; + } + for (i = 0; i < code_bytes; i++, eip++) { if (eip < (u8 __user *)PAGE_OFFSET || __get_user(c, eip)) { printk(" Bad EIP value."); break; -- Chuck