From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933943Ab1KCQIr (ORCPT ); Thu, 3 Nov 2011 12:08:47 -0400 Received: from mail-fx0-f46.google.com ([209.85.161.46]:38424 "EHLO mail-fx0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933739Ab1KCQIp (ORCPT ); Thu, 3 Nov 2011 12:08:45 -0400 Message-ID: <4EB2BC88.3070105@suse.cz> Date: Thu, 03 Nov 2011 17:08:40 +0100 From: Jiri Slaby User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:7.0.1) Gecko/20110929 Thunderbird/7.0.1 MIME-Version: 1.0 To: Jens Axboe CC: Tejun Heo , "James E.J. Bottomley" , LKML , linux-scsi , Jiri Slaby Subject: NULL ptr deref at elv_drain_elevator X-Enigmail-Version: 1.4a1pre Content-Type: text/plain; charset=ISO-8859-2 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, I'm seeing the NULL ptr dereference below on each boot of KVM virtual machine. q->elevator is NULL. This is next-20111025. I tried to apply Tejun's patch from: https://lkml.org/lkml/2011/4/30/87 but it doesn't help. Maybe I should revert something? Scanning for LVM volume groups... Reading all physical volumes. This may take a while... No volume groups found BUG: unable to handle kernel NULL pointer dereference at (null) IP: [] elv_drain_elevator+0x1c/0x70 PGD 46176067 PUD 452b5067 PMD 0 Oops: 0000 [#1] SMP CPU 0 Modules linked in: Pid: 830, comm: kworker/0:2 Not tainted 3.1.0-next-20111025_64+ #1590 Bochs Bochs RIP: 0010:[] [] elv_drain_elevator+0x1c/0x70 RSP: 0018:ffff8800461abd00 EFLAGS: 00010086 RAX: 0000000000000000 RBX: ffff880046948e00 RCX: 00000001820001ee RDX: 0000000000000001 RSI: 0000000000000001 RDI: ffff880046948e00 RBP: ffff8800461abd10 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000001 R13: ffff8800469494e0 R14: ffff88004689c450 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff880049600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b CR2: 0000000000000000 CR3: 00000000451f6000 CR4: 00000000000006f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Process kworker/0:2 (pid: 830, threadinfo ffff8800461aa000, task ffff880046f28670) Stack: ffff88004789f888 ffff880046948e00 ffff8800461abd30 ffffffff8125da92 ffff880046948e00 ffff8800469491f4 ffff8800461abd60 ffffffff8125db90 ffff8800461abd40 ffff88004689c450 ffff88004689c400 ffff88004789f888 Call Trace: [] blk_drain_queue+0x42/0x70 [] blk_cleanup_queue+0xd0/0x1c0 [] md_free+0x50/0x70 [] kobject_release+0x8b/0x1d0 [] ? kobject_del+0x40/0x40 [] ? bb_show+0x20/0x20 [] kref_put+0x36/0xa0 [] kobject_put+0x27/0x60 [] mddev_delayed_delete+0x2f/0x40 [] process_one_work+0x100/0x3b0 [] worker_thread+0x15f/0x3a0 [] ? manage_workers.isra.32+0x240/0x240 [] kthread+0x87/0x90 [] kernel_thread_helper+0x4/0x10 [] ? kthread_worker_fn+0x1a0/0x1a0 [] ? gs_change+0xb/0xb Code: c0 74 02 ff d0 5d c3 0f 1f 84 00 00 00 00 00 55 48 89 e5 53 48 89 fb 48 83 ec 08 0f 1f 40 00 48 8b 43 18 be 01 00 00 00 48 89 df 8b 00 ff 50 28 85 c0 75 ea 8b 93 80 04 00 00 85 d2 74 14 8b RIP [] elv_drain_elevator+0x1c/0x70 RSP CR2: 0000000000000000 ---[ end trace 2b4616ccecf0982b ]--- thanks, -- js suse labs