From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752636Ab2LDTUc (ORCPT ); Tue, 4 Dec 2012 14:20:32 -0500 Received: from out01.mta.xmission.com ([166.70.13.231]:39673 "EHLO out01.mta.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751090Ab2LDTUb (ORCPT ); Tue, 4 Dec 2012 14:20:31 -0500 From: ebiederm@xmission.com (Eric W. Biederman) To: "Bill Huey \(hui\)" Cc: Linux Kernel Mailing List References: Date: Tue, 04 Dec 2012 11:20:25 -0800 In-Reply-To: (Bill Huey's message of "Tue, 4 Dec 2012 06:03:09 -0800") Message-ID: <87txs162va.fsf@xmission.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-XM-AID: U2FsdGVkX19MV4B1k3x6vvIccg0RiZt/K9U3nSeEzcw= X-SA-Exim-Connect-IP: 98.207.153.68 X-SA-Exim-Mail-From: ebiederm@xmission.com X-Spam-Report: * -1.0 ALL_TRUSTED Passed through trusted hosts only via SMTP * 0.0 T_TM2_M_HEADER_IN_MSG BODY: T_TM2_M_HEADER_IN_MSG * 0.6 FUZZY_AMBIEN BODY: Attempt to obfuscate words in spam * -0.0 BAYES_20 BODY: Bayes spam probability is 5 to 20% * [score: 0.0931] * -0.0 DCC_CHECK_NEGATIVE Not listed in DCC * [sa07 1397; Body=1 Fuz1=1 Fuz2=1] X-Spam-DCC: XMission; sa07 1397; Body=1 Fuz1=1 Fuz2=1 X-Spam-Combo: ;"Bill Huey \(hui\)" X-Spam-Relay-Country: Subject: Re: BUG: wait_task_zombie NULL dereference X-SA-Exim-Version: 4.2.1 (built Sun, 08 Jan 2012 03:05:19 +0000) X-SA-Exim-Scanned: Yes (on in02.mta.xmission.com) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org "Bill Huey (hui)" writes: > I should add that I encountered this on 3.6.0 with some mild > modifications to the scheduler path that enqueue/dequeue a task before > any of the schedule exit logic gets hit. The SCHED_FF/FIFO rebalancer > does much the same so I can't imagine that being the source of the > problem. > > I could be wrong however. In 3.6 from_kuid_munged should be only be expanded to the inline noop version. The code you quote does not exist in kernel/exit.c in wait_task_zombie and has not existed in wait_task_zombie in Linus's tree. So since I can't see the code I can't help. I suspect the bug relates to your local modifications. Eric