From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Mon, 7 May 2001 19:05:33 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Mon, 7 May 2001 19:05:23 -0400 Received: from pobox.sibyte.com ([208.12.96.20]:63749 "HELO pobox.sibyte.com") by vger.kernel.org with SMTP id ; Mon, 7 May 2001 19:05:15 -0400 From: Justin Carlson Reply-To: carlson@sibyte.com Organization: Sibyte To: linux-kernel@vger.kernel.org Subject: SMP bug revealed by networking? Date: Mon, 7 May 2001 15:54:14 -0700 X-Mailer: KMail [version 1.0.29] Content-Type: text/plain; charset=US-ASCII MIME-Version: 1.0 Message-Id: <0105071604481H.00781@plugh.sibyte.com> Content-Transfer-Encoding: 7BIT Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org I'm working on a new SMP mips port, and tripped over a strange bug. Am not quite sure how to attack it. I'm running 2.4.2 from oss.sgi.com's cvs repositry, booting with the root filesystem being over NFS with two cores active in the system. The port is actually fairly stable at the moment, but just once, while trying to exec init during a boot, it locked up. Since I'm running in simulation (fun consequence of not porting to something for which silicon doesn't yet exist), I took a peek and saw this: CPU0 was in ip_defrag() trying to aquire the ipq spinlock CPU1 was idle. ip_defrag() being an exceedingly unlikely source of bugs at this moment, especially in terms of that simple locking, I'm thinking I must have a bug in the SMP handling; however, I don't see any likely candidates there either. I can't reproduce this bug, either; it seems to have been dependent on timing from the network. Has anyone run into anything remotely like this before? Any suggestions on where to look for bug or how to make this reproducable in order to track it down? Thanks, Justin