From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752229AbXCSMlY (ORCPT ); Mon, 19 Mar 2007 08:41:24 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752203AbXCSMlY (ORCPT ); Mon, 19 Mar 2007 08:41:24 -0400 Received: from caramon.arm.linux.org.uk ([217.147.92.249]:4516 "EHLO caramon.arm.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751559AbXCSMlX (ORCPT ); Mon, 19 Mar 2007 08:41:23 -0400 Date: Mon, 19 Mar 2007 12:41:14 +0000 From: Russell King To: railroad seeker Cc: linux-kernel@vger.kernel.org Subject: Re: Scheduling in interrupt and call trace Message-ID: <20070319124114.GA13850@flint.arm.linux.org.uk> Mail-Followup-To: railroad seeker , linux-kernel@vger.kernel.org References: <6eb6ed920703190537o3c4738d6l61dd946d9554b4a3@mail.gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <6eb6ed920703190537o3c4738d6l61dd946d9554b4a3@mail.gmail.com> User-Agent: Mutt/1.4.2.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Mar 19, 2007 at 08:37:57PM +0800, railroad seeker wrote: > After that, the program counter must located in BUG(), that is something > like > "(void *)0 = 0" if we really do scheduling in interrupt contxt, and > should cause > the kernel to panic. However, what i got is that the latest program > counter is located within the do_IRQ() context when the kernel was > crashed . But it > seems that the stack trace is a kernel stack of process context since > the bottom of the stack is ret_from_syscall. (I have not enabled the > frame pointer when compiling the kernel, instead, I back traced by > manually inspect each 32 bit value > from the output of objdump) , and I think that the latest PC should > point to the next instruction of "(void *) 0 = 0". > > Is there any possibility with which we got this incorrect information, > or I have > misunderstanding about "kernel system to interrupt context switch? Please enable frame pointers and show the resulting backtrace; it is possible that trying to manually decode the stack without frame pointers enabled will result in a confused backtrace. -- Russell King Linux kernel 2.6 ARM Linux - http://www.arm.linux.org.uk/ maintainer of: