Re: [regression] CD-ROM polling blocks suspend on some machines(Re: [PATCH 1/2] cdrom: always check_disk_change() on open)

From: Tejun Heo
Date: Sun Oct 30 2011 - 16:35:20 EST


On Fri, Oct 28, 2011 at 03:47:43PM +0200, Matthijs Kooijman wrote:
> I'm not sure if the FRAME_POINTER option actually works, though, since I
> couldn't find any obvious differences in the format of the stack traces?

The lines w/o leading "?" are from stack frames discovered by
following frame pointer. The ones w/ "?" are from dumb stack
scanning. w/o FP, it wouldn't be possible to tell between the actual
ones from the spurious ones.

So, the following kworker is what the scsi_id is waiting for in

kworker/2:1 D ffff880206054830 0 10775 2 0x00000000
ffff880206067aa0 0000000000000046 ffff880206067a50 ffffffff8105476d
ffff88022ed58140 ffff880206067fd8 ffff880206067fd8 0000000000012f40
ffff880206054830 ffff88022ed58140 ffff880200000002 0000000000000286
Call Trace:
[<ffffffff8134c996>] schedule+0x55/0x57
[<ffffffff8134cc9f>] schedule_timeout+0xa2/0xd9
[<ffffffff8134c832>] wait_for_common+0x9e/0x115
[<ffffffff8134c925>] wait_for_completion_timeout+0xe/0x10
[<ffffffff8119c502>] blk_execute_rq+0xb7/0xf9
[<ffffffffa0043044>] scsi_execute+0xf5/0x14d [scsi_mod]
[<ffffffffa004311e>] scsi_execute_req+0x82/0xb4 [scsi_mod]
[<ffffffffa00bb2d9>] sr_check_events+0x92/0x21e [sr_mod]
[<ffffffffa009d04b>] cdrom_check_events+0x14/0x29 [cdrom]
[<ffffffffa00bb696>] sr_block_check_events+0x14/0x16 [sr_mod]
[<ffffffff8119ea7b>] disk_events_workfn+0x3b/0xd7
[<ffffffff8105dcc9>] process_one_work+0x165/0x27a
[<ffffffff8105ed4f>] worker_thread+0xce/0x152
[<ffffffff81061f6c>] kthread+0x7f/0x87
[<ffffffff81355034>] kernel_thread_helper+0x4/0x10

The kworker submitted request but it got lost during queue destruction
and blk_execute_rq() hangs. There have been a number of recent
changes in block devel tree to address this issue. Can you please
test the following branch?

git:// block-ref


To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at
Please read the FAQ at