On 2011-11-03 17:26, Tejun Heo wrote: > blk_cleanup_queue() may be called before elevator is set up on a > queue which triggers the following oops. > > BUG: unable to handle kernel NULL pointer dereference at (null) > IP: [<ffffffff8125a69c>] elv_drain_elevator+0x1c/0x70 > ... > Pid: 830, comm: kworker/0:2 Not tainted 3.1.0-next-20111025_64+ #1590 > Bochs Bochs > RIP: 0010:[<ffffffff8125a69c>] [<ffffffff8125a69c>] elv_drain_elevator+0x1c/0x70 > ... > Call Trace: > [<ffffffff8125da92>] blk_drain_queue+0x42/0x70 > [<ffffffff8125db90>] blk_cleanup_queue+0xd0/0x1c0 > [<ffffffff81469640>] md_free+0x50/0x70 > [<ffffffff8126f43b>] kobject_release+0x8b/0x1d0 > [<ffffffff81270d56>] kref_put+0x36/0xa0 > [<ffffffff8126f2b7>] kobject_put+0x27/0x60 > [<ffffffff814693af>] mddev_delayed_delete+0x2f/0x40 > [<ffffffff81083450>] process_one_work+0x100/0x3b0 > [<ffffffff8108527f>] worker_thread+0x15f/0x3a0 > [<ffffffff81089937>] kthread+0x87/0x90 > [<ffffffff81621834>] kernel_thread_helper+0x4/0x10 > > Fix it by making blk_cleanup_queue() check whether q->elevator is set > up before invoking blk_drain_queue. Thanks, glad this got caught before the merge... -- Jens Axboe -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
