Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S966051AbXJPXbc (ORCPT ); Tue, 16 Oct 2007 19:31:32 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755601AbXJPXbX (ORCPT ); Tue, 16 Oct 2007 19:31:23 -0400 Received: from wa-out-1112.google.com ([209.85.146.179]:20387 "EHLO wa-out-1112.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752572AbXJPXbW (ORCPT ); Tue, 16 Oct 2007 19:31:22 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=beta; h=received:message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=XJDClVfpIR8re9n1lY6yn2cKksySduWd12o5beLkQrY+Bo/ggKgbjBs/EWjbasbvMr+2SekSrDFjmD5wwGuUPg8iWhVptHoz7UmqsmO3MDW119c9dkzgkSlVmEyhn/vx5CTQ8XoNoS3JvtvJ0GLeZelCSqEtameaG7pGpZrQuzU= Message-ID: Date: Wed, 17 Oct 2007 01:31:22 +0200 From: "Dmitry Adamushko" To: "Gabriel C" , "Srivatsa Vaddagiri" Subject: Re: [git pull] scheduler updates for v2.6.24 Cc: "Ingo Molnar" , "Andrew Morton" , torvalds@linux-foundation.org, linux-kernel@vger.kernel.org In-Reply-To: <4715378A.4050806@googlemail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <20071015141723.GA29486@elte.hu> <20071015113527.6bf91baf.akpm@linux-foundation.org> <20071015185307.GA26763@elte.hu> <4715378A.4050806@googlemail.com> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1562 Lines: 42 [ cc'ed Srivatsa ] On 17/10/2007, Gabriel C wrote: > Ingo Molnar wrote: > [15692.917111] BUG: unable to handle kernel NULL pointer dereference at virtual address 00000044 > ... > [15692.917629] EFLAGS: 00010046 (2.6.23-g65a6ec0d #330) > [15692.917661] EIP is at pick_next_task_fair+0x1f/0x2d Gabriel, could you please post a disassembled code for pick_next_task_fair()? (objdump -d kernel/sched.o and then search for pick_next_task_fair -- copy_and_past) anyway, my guess is that it's : se = pick_next_entity(cfs_rq); cfs_rq = group_cfs_rq(se); 'se' _happens_ to be NULL and group_cf_rq(se) does se->my_q and (according to my calculations) offset(my_q) == 68 (0x44) for x86 32bit system with CONFIG_SCHEDSTATS=n and CONFIG_FAIR_GROUP_SCHED=y (according to the config). that might take place provided put_prev_task_fair() failed for some reason to insert 'current' (or its corresponding group element) back into the tree in schedule()... say, due to some inconsistency in cfs_rq's data. Srivatsa, that's somewhat similar to another issue that has been posted earlier today (crash in put_prev_task_fair() --> __enqueue_task() --> rb_insert_color()) that you are already aware of ... (/me will continue tomorrow). -- Best regards, Dmitry Adamushko - 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/