Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S265361AbUFSKAf (ORCPT ); Sat, 19 Jun 2004 06:00:35 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S265366AbUFSKAf (ORCPT ); Sat, 19 Jun 2004 06:00:35 -0400 Received: from holomorphy.com ([207.189.100.168]:62860 "EHLO holomorphy.com") by vger.kernel.org with ESMTP id S265361AbUFSKAe (ORCPT ); Sat, 19 Jun 2004 06:00:34 -0400 Date: Sat, 19 Jun 2004 02:59:10 -0700 From: William Lee Irwin III To: Andrew Morton Cc: Keith Owens , linux-kernel@vger.kernel.org Subject: Re: [patch 2.6.7] bug_smp_call_function Message-ID: <20040619095910.GQ1863@holomorphy.com> Mail-Followup-To: William Lee Irwin III , Andrew Morton , Keith Owens , linux-kernel@vger.kernel.org References: <5328.1087637808@kao2.melbourne.sgi.com> <20040619024416.065f4026.akpm@osdl.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20040619024416.065f4026.akpm@osdl.org> User-Agent: Mutt/1.5.5.1+cvs20040105i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1262 Lines: 26 Keith Owens wrote: >> sg.c has been fixed to no longer call vfree() with interrupts disabled. >> Change smp_call_function() from WARN_ON to BUG_ON when interrupts are >> disabled. It was only set to WARN_ON because of sg.c. On Sat, Jun 19, 2004 at 02:44:16AM -0700, Andrew Morton wrote: > I prefer the WARN_ON. It is exceedingly unlikely that the bug will cause > lockups or memory/data corruption or anything else, so why nuke the user's > box when we can trivially continue? > We'll be sent the bug report either way. Calls to smp_call_function() with interrupts off or spinlocks held typically causes deadlocks on SMP systems. ISTR debugging such an issue in the scheduler a while back, i.e. mmdrop() under rq->lock doing vfree() of an LDT. Basically smp_call_function() will spin waiting for the other cpus to answer the interrupt on multiple cpus. It also doesn't need to be the same function doing smp_call_function(); generally TLB flushing deadlocks against anything doing this. -- wli - 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/