Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755471Ab2FNJmV (ORCPT ); Thu, 14 Jun 2012 05:42:21 -0400 Received: from mail-we0-f174.google.com ([74.125.82.174]:60757 "EHLO mail-we0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754354Ab2FNJmU (ORCPT ); Thu, 14 Jun 2012 05:42:20 -0400 Message-ID: <4FD9B1F7.1040107@suse.cz> Date: Thu, 14 Jun 2012 11:42:15 +0200 From: Jiri Slaby User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:15.0) Gecko/20120610 Thunderbird/15.0a2 MIME-Version: 1.0 To: Jens Axboe CC: Tejun Heo , LKML , Jiri Slaby , Asias He Subject: Re: NULL pointer dereference at blk_drain_queue References: <4FD9A908.90307@suse.cz> <4FD9ABFE.8060603@kernel.dk> In-Reply-To: <4FD9ABFE.8060603@kernel.dk> X-Enigmail-Version: 1.4.2 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 Content-Length: 3827 Lines: 87 On 06/14/2012 11:16 AM, Jens Axboe wrote: > On 06/14/2012 11:04 AM, Jiri Slaby wrote: >> Hi, >> >> with today's -next I'm (reproducibly) getting this while updating packages: >> BUG: unable to handle kernel NULL pointer dereference at (null) >> IP: [] __wake_up_common+0x26/0x90 >> PGD 463f1067 PUD 463f2067 PMD 0 >> Oops: 0000 [#1] SMP >> CPU 1 >> Modules linked in: >> Pid: 2711, comm: kworker/1:0 Not tainted 3.5.0-rc2-next-20120614_64+ >> #1752 Bochs Bochs >> RIP: 0010:[] [] >> __wake_up_common+0x26/0x90 >> RSP: 0018:ffff880047221cb0 EFLAGS: 00010082 >> RAX: 0000000000000086 RBX: ffff880046350888 RCX: 0000000000000000 >> RDX: 0000000000000000 RSI: 0000000000000003 RDI: ffff880046350888 >> RBP: ffff880047221cf0 R08: 0000000000000000 R09: 00000001000c0009 >> R10: ffff880047804480 R11: 0000000000000000 R12: ffff880046350890 >> R13: 0000000000000003 R14: 0000000000000000 R15: 0000000000000003 >> FS: 0000000000000000(0000) GS:ffff880049700000(0000) knlGS:0000000000000000 >> CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b >> CR2: 0000000000000000 CR3: 0000000045ced000 CR4: 00000000000006e0 >> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 >> DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 >> Process kworker/1:0 (pid: 2711, threadinfo ffff880047220000, task >> ffff8800435bc5c0) >> Stack: >> 000000004628da68 0000000000000000 ffff88004970d340 ffff880046350888 >> 0000000000000086 0000000000000003 0000000000000000 0000000000000000 >> ffff880047221d30 ffffffff8108d9a3 ffff88004970d340 ffff880046350848 >> Call Trace: >> [] __wake_up+0x43/0x70 >> [] blk_drain_queue+0xf6/0x120 >> [] blk_cleanup_queue+0x7f/0xd0 >> [] md_free+0x50/0x70 >> [] kobject_cleanup+0x82/0x1b0 >> [] kobject_put+0x2b/0x60 >> [] mddev_delayed_delete+0x2f/0x40 >> [] process_one_work+0x11b/0x3f0 >> [] ? restart_array+0xc0/0xc0 >> [] worker_thread+0x12e/0x340 >> [] ? manage_workers.isra.29+0x1f0/0x1f0 >> [] kthread+0x8e/0xa0 >> [] kernel_thread_helper+0x4/0x10 >> [] ? flush_kthread_worker+0x70/0x70 >> [] ? gs_change+0xb/0xb >> Code: 80 00 00 00 00 55 48 89 e5 41 57 41 89 f7 41 56 41 89 ce 41 55 41 >> 54 4c 8d 67 08 53 48 83 ec 18 89 55 c4 48 8b 57 08 4c 89 45 c8 <4c> 8b >> 2a 48 8d 42 e8 49 83 ed 18 49 39 d4 75 0d eb 40 0f 1f 84 > > It's a bug in local commit bc85cf83, for stacked devices we have not > initialized the wait queues. So the below should fix it, as would always > initializing all queue structures even for the partial use case. > > > diff --git a/block/blk-core.c b/block/blk-core.c > index b477fa0..93eb3e4 100644 > --- a/block/blk-core.c > +++ b/block/blk-core.c > @@ -415,10 +415,12 @@ void blk_drain_queue(struct request_queue *q, bool drain_all) > * allocation path, so the wakeup chaining is lost and we're > * left with hung waiters. We need to wake up those waiters. > */ > - spin_lock_irq(q->queue_lock); > - for (i = 0; i < ARRAY_SIZE(q->rq.wait); i++) > - wake_up_all(&q->rq.wait[i]); > - spin_unlock_irq(q->queue_lock); > + if (q->request_fn) { > + spin_lock_irq(q->queue_lock); > + for (i = 0; i < ARRAY_SIZE(q->rq.wait); i++) > + wake_up_all(&q->rq.wait[i]); > + spin_unlock_irq(q->queue_lock); > + } Yes, that fixed it. thanks, -- js suse labs -- 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/