Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751379AbXBVF6b (ORCPT ); Thu, 22 Feb 2007 00:58:31 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751389AbXBVF6b (ORCPT ); Thu, 22 Feb 2007 00:58:31 -0500 Received: from terminus.zytor.com ([192.83.249.54]:60691 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751379AbXBVF6b (ORCPT ); Thu, 22 Feb 2007 00:58:31 -0500 Message-ID: <45DD30DE.20503@zytor.com> Date: Wed, 21 Feb 2007 21:57:50 -0800 From: "H. Peter Anvin" User-Agent: Thunderbird 1.5.0.9 (X11/20061219) MIME-Version: 1.0 To: Jose Goncalves , Frederik Deweerdt , akpm@linux-foundation.org, linux-kernel@vger.kernel.org Subject: Re: Serial related oops References: <20070219134539.GA27370@flint.arm.linux.org.uk> <20070220142442.GF566@slug> <20070219143520.GB27370@flint.arm.linux.org.uk> <20070220144814.GJ566@slug> <20070219150508.GD27370@flint.arm.linux.org.uk> <45D9D073.7020701@inov.pt> <20070219164200.GF27370@flint.arm.linux.org.uk> <45D9E46C.4030408@inov.pt> <20070219212347.GA4258@flint.arm.linux.org.uk> <45DC537B.6020108@inov.pt> <20070221230503.GA28156@flint.arm.linux.org.uk> In-Reply-To: <20070221230503.GA28156@flint.arm.linux.org.uk> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1101 Lines: 33 Russell King wrote: > > Plainly, %ebx changed across the call to serial_in() at c01c0f7b. > First thing to notice is this violates the C code - "up" can not > change. > > Now let's look at serial_in: > > c01bfa70: 55 push %ebp > c01bfa71: 89 e5 mov %esp,%ebp > c01bfa73: 53 push %ebx > ... > c01bfab7: 5b pop %ebx > c01bfab8: 5d pop %ebp > c01bfab9: c3 ret > > This code tells the CPU to preserves %ebx and %ebp. But we know %ebx > _wasn't_ preserved. Ergo, your CPU is plainly not doing what the code > told it to do. > ... assuming nothing else clobbered the stack slot (which would be a compiler error, or a wild pointer.) Got a disassembly of the whole function? -hpa - 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/