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, 22 Apr 2002 12:08:33 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Mon, 22 Apr 2002 12:08:32 -0400 Received: from [195.39.17.254] ([195.39.17.254]:38542 "EHLO Elf.ucw.cz") by vger.kernel.org with ESMTP id ; Mon, 22 Apr 2002 12:08:30 -0400 Date: Sun, 21 Apr 2002 18:57:05 +0000 From: Pavel Machek To: Robert Love Cc: dipankar@in.ibm.com, linux-kernel@vger.kernel.org Subject: Re: 2.5.8: preemption + SMP broken ? Message-ID: <20020421185705.B155@toy.ucw.cz> In-Reply-To: <20020417232253.A629@in.ibm.com> <1019067957.1669.46.camel@phantasy> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Mailer: Mutt 1.0.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Hi! > > My machine (4cpu x86) hangs while booting a kernel with SMP > > and preemption enabled. It hangs while executing one of > > the initcalls, probably BIO since that is where the > > next boot message comes from during a successful boot with SMP > > (or preemption) disabled. > > > > Has anyone tried out preemption with SMP ? > > Sure, all my testing is on SMP. The problem manifested itself in > 2.5.8-pre when some changes where made to the migration code. The race > is in the migration code - I am not sure it is preempts fault, per se, > but the attached patch should fix it. It is pending with Linus for the > next release. Wel, if race is in migration code, you should fix migration, not add preempt_disable(), right? [Or is race preempt-onlly?] -- Philips Velo 1: 1"x4"x8", 300gram, 60, 12MB, 40bogomips, linux, mutt, details at http://atrey.karlin.mff.cuni.cz/~pavel/velo/index.html.