From mboxrd@z Thu Jan 1 00:00:00 1970 From: walt Subject: Real-life kernel debugging scenario Date: Mon, 07 Nov 2005 16:51:50 -0800 Organization: none Message-ID: Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-From: git-owner@vger.kernel.org Tue Nov 08 01:55:57 2005 Return-path: Received: from vger.kernel.org ([209.132.176.167]) by ciao.gmane.org with esmtp (Exim 4.43) id 1EZHkt-0004pY-US for gcvg-git@gmane.org; Tue, 08 Nov 2005 01:54:32 +0100 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030216AbVKHAy2 (ORCPT ); Mon, 7 Nov 2005 19:54:28 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1030218AbVKHAy2 (ORCPT ); Mon, 7 Nov 2005 19:54:28 -0500 Received: from main.gmane.org ([80.91.229.2]:24707 "EHLO ciao.gmane.org") by vger.kernel.org with ESMTP id S1030216AbVKHAy1 (ORCPT ); Mon, 7 Nov 2005 19:54:27 -0500 Received: from list by ciao.gmane.org with local (Exim 4.43) id 1EZHjT-0004Q1-Vv for git@vger.kernel.org; Tue, 08 Nov 2005 01:53:04 +0100 Received: from adsl-69-234-218-246.dsl.irvnca.pacbell.net ([69.234.218.246]) by main.gmane.org with esmtp (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Tue, 08 Nov 2005 01:53:03 +0100 Received: from wa1ter by adsl-69-234-218-246.dsl.irvnca.pacbell.net with local (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Tue, 08 Nov 2005 01:53:03 +0100 X-Injected-Via-Gmane: http://gmane.org/ To: git@vger.kernel.org X-Complaints-To: usenet@sea.gmane.org X-Gmane-NNTP-Posting-Host: adsl-69-234-218-246.dsl.irvnca.pacbell.net User-Agent: Mail/News 1.6a1 (X11/20051106) Sender: git-owner@vger.kernel.org Precedence: bulk X-Mailing-List: git@vger.kernel.org Archived-At: This describes a real problem I've had twice in the last two years while tracking Linus's kernel tree: I update my local kernel sources every morning using cg-update (formerly bk-pull) and compile and install and reboot the new kernel. Okay. On rare occasions I get a kernel panic on reboot. So... I know that something Linus committed in the last 24 hours is responsible for the problem. The last two times this happened I was able to guess which commit caused the problem and I emailed the developer off- list and got the problem fixed very quickly. (This is why I love open-source software!) My worry: what happens when I'm not smart enough to guess which developer to email? My first instinct is to back out the most recent commits one-by-one until the bug goes away. First: is this an optimal tactic? Second: how to back out individual commits using git or cogito? I suppose this is already spelled out in the docs, but I invite everyone to point me to the relevant places in the docs that have escaped my attention so far. Thanks!