From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761463AbYCFVpn (ORCPT ); Thu, 6 Mar 2008 16:45:43 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752162AbYCFVpd (ORCPT ); Thu, 6 Mar 2008 16:45:33 -0500 Received: from mx2.mail.elte.hu ([157.181.151.9]:47851 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751497AbYCFVpc (ORCPT ); Thu, 6 Mar 2008 16:45:32 -0500 Date: Thu, 6 Mar 2008 22:45:16 +0100 From: Ingo Molnar To: Pekka Enberg Cc: Jens Osterkamp , Christoph Lameter , linux-mm@kvack.org, Linux kernel mailing list Subject: Re: [BUG] in 2.6.25-rc3 with 64k page size and SLUB_DEBUG_ON Message-ID: <20080306214516.GB886@elte.hu> References: <200803061447.05797.Jens.Osterkamp@gmx.de> <84144f020803061327r2310b23ew6211bc09f9ba25a3@mail.gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <84144f020803061327r2310b23ew6211bc09f9ba25a3@mail.gmail.com> User-Agent: Mutt/1.5.17 (2007-11-01) X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -1.5 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.5 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.3 -1.5 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Pekka Enberg wrote: > > Mount-cache hash table entries: 4096 > > BUG: scheduling while atomic: kthreadd/2/0x00056ef8 > > Call Trace: > > [c00000003c187b68] [c00000000000f140] .show_stack+0x70/0x1bc (unreliable) > > [c00000003c187c18] [c000000000052d0c] .__schedule_bug+0x64/0x80 > > [c00000003c187ca8] [c00000000036fa84] .schedule+0xc4/0x6b0 > > [c00000003c187d98] [c0000000003702d0] .schedule_timeout+0x3c/0xe8 > > [c00000003c187e68] [c00000000036f82c] .wait_for_common+0x150/0x22c > > [c00000003c187f28] [c000000000074868] .kthreadd+0x12c/0x1f0 > > [c00000003c187fd8] [c000000000024864] .kernel_thread+0x4c/0x68 > > ------------[ cut here ]------------ > > kernel BUG at /home/auto/jens/kernels/linux-2.6.25-rc3/kernel/sched.c:4532! > > cpu 0x0: Vector: 700 (Program Check) at [c00000003c187bc8] > > pc: c000000000051f8c: .sched_setscheduler+0x5c/0x48c > > lr: c0000000000748b0: .kthreadd+0x174/0x1f0 > > sp: c00000003c187e48 > > msr: 9000000000029032 > > current = 0xc00000007e0808a0 > > paca = 0xc0000000004cf880 > > pid = 2, comm = kthreadd > > kernel BUG at /home/auto/jens/kernels/linux-2.6.25-rc3/kernel/sched.c:4532! > > enter ? for help > > [c00000003c187f28] c0000000000748b0 .kthreadd+0x174/0x1f0 > > [c00000003c187fd8] c000000000024864 .kernel_thread+0x4c/0x68 > > 0:mon> > > > > In the code this corresponds to > > > > int sched_setscheduler(struct task_struct *p, int policy, > > struct sched_param *param) > > { > > int retval, oldprio, oldpolicy = -1, on_rq, running; > > unsigned long flags; > > const struct sched_class *prev_class = p->sched_class; > > struct rq *rq; > > > > /* may grab non-irq protected spin_locks */ > > BUG_ON(in_interrupt()); > > recheck: > > /* double check policy once rq lock held */ > > if (policy < 0) > > policy = oldpolicy = p->policy; > > else if (policy != SCHED_FIFO && policy != SCHED_RR && > > policy != SCHED_NORMAL && policy != SCHED_BATCH && > > policy != SCHED_IDLE) > > return -EINVAL; > > > > With slub_debug=- on the kernel command line, the problem is gone. > > With 4k page size the problem also does not occur. > > > > Any ideas on why this occurs and how to debug this further ? > > There's no SLUB in the stack traces. Ingo, any suggestions how to debug this? hm, no idea - is this powerpc? It seems to have hit a atomicity check due to: > > BUG: scheduling while atomic: kthreadd/2/0x00056ef8 preempt-count 0x00056ef8 is totally out of whack. Serious memory corruption. Ingo