On 7/20/22 00:47, Geert Uytterhoeven wrote:
With more debug options enabled, it prints:
INFO: task kworker/0:7:283 blocked for more than 120 seconds.
Not tainted 5.19.0-rc7-salvator-x-00794-g6780eb02b605 #1287
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/0:7 state:D stack: 0 pid: 283 ppid: 2 flags:0x00000008
Workqueue: events ata_scsi_dev_rescan
Call trace:
__switch_to+0xbc/0x124
__schedule+0x540/0x71c
schedule+0x58/0xa0
io_schedule+0x18/0x34
blk_mq_get_tag+0x138/0x244
__blk_mq_alloc_requests+0x130/0x2f0
blk_mq_alloc_request+0x74/0xa8
scsi_alloc_request+0x10/0x30
__scsi_execute+0x5c/0x18c
scsi_vpd_inquiry+0x7c/0xdc
scsi_get_vpd_size+0x34/0xa8
scsi_get_vpd_buf+0x28/0xf4
scsi_attach_vpd+0x44/0x170
scsi_rescan_device+0x30/0x98
ata_scsi_dev_rescan+0xc8/0xfc
process_one_work+0x2e0/0x474
worker_thread+0x1cc/0x270
kthread+0xd8/0xe8
ret_from_fork+0x10/0x20
This doesn't look like it's blocked in the R-Car SATA driver, but on
some I/O scheduling event in the block core?
I'm not familiar with the SATA code but from a quick look it seems like
the above code is only triggered from inside the ATA error handler
(ata_do_eh() -> ata_eh_recover() -> ata_eh_revalidate_and_attach() ->
schedule_work(&(ap->scsi_rescan_task) -> ata_scsi_dev_rescan()). It
doesn't seem normal to me that the ATA error handler gets invoked during
a resume. How about testing the following two code changes?
* In sd_start_stop_device(), change "return sd_submit_start(sdkp, cmd,
sizeof(cmd))" into "sd_submit_start(sdkp, cmd, sizeof(cmd))" and below
that call add "flush_work(&sdkp->start_done_work)". This makes
sd_start_stop_device() again synchronous. This will learn us whether the
behavior change is caused by submitting the START command from another
context or by not waiting until the START command has finished.
* Back out the above change, change "return sd_submit_start(sdkp, cmd,
sizeof(cmd))" again into "sd_submit_start(sdkp, cmd, sizeof(cmd))" and
below that statement add a call to
scsi_run_queue(sdkp->device->request_queue). If this change helps it
means that the scsi_run_queue() call is necessary to prevent reordering
of the START command with other SCSI commands.
Thanks,
Bart.
