Re: problem booting 5.10

Linus Torvalds
2020-12-08T18:32:51Z

On Tue, Dec 8, 2020 at 9:37 AM Julia Lawall <julia.lawall@inria.fr> wrote:
>
> We have not succeeded to boot 5.10 on our Intel(R) Xeon(R) CPU E7-8870 v4 @
> 2.10GHz server. Previous versions (eg 4.19 - 5.9) boot fine. We have
> tried various rcs.

So the problem started with rc1?

Could you try bisecting - even partially? If you do only six
bisections, the number of suspect commits drops from 15k to about 230
- which likely pinpoints the suspect area.

That said, your traces certainly makes me go "Hmm. Some thing broke in
SCSI device scanning", with the primary one being the
wait_for_completion() one - the rest of the stuck processes seem to be
stuck in async_synchronize_cookie_domain() and are presumably waiting
for this kthread that is waiting for the scan to finish.

So I'm adding SCSI people to the cc, just in case they go "Hmm..".

Martin & co - in the next email Julia also quotes

> [ 51.355655][ T7] scsi 0:0:14:0: Direct-Access ATA ST2000LM015-2E81 SDM1 PQ: 0 ANSI: 6
> Gave up waiting for root file system device. Common problems:[..]

which seems to be more of the same pattern with the SCSI scanning failure.

Of course, it could be some non-scsi patch that causes this, but.. A
bisect would hopefully clarify.

Leaving the (simplified) backtrace quoted below.

Linus

>The backtrace for rc7 is shown below.
>
> [ 253.207171][ T979] INFO: task kworker/u321:2:1278 blocked for more than 120 seconds.
> [ 253.224089][ T979] Tainted: G E 5.10.0-rc7 #3
> [ 253.239209][ T979] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
> [ 253.256990][ T979] task:kworker/u321:2 state:D stack: 0 pid: 1278 ppid: 2 flags:0x00004000
> [ 253.275552][ T979] Workqueue: events_unbound async_run_entry_fn
> [ 253.290687][ T979] Call Trace:
> [ 253.302491][ T979] __schedule+0x31e/0x890
> [ 253.315353][ T979] schedule+0x3c/0xa0
> [ 253.327688][ T979] schedule_timeout+0x274/0x310
> [ 253.379283][ T979] wait_for_completion+0x8a/0xf0
> [ 253.392327][ T979] scsi_complete_async_scans+0x107/0x170
> [ 253.406115][ T979] __scsi_add_device+0xf7/0x130
> [ 253.418974][ T979] ata_scsi_scan_host+0x98/0x1c0
> [ 253.431948][ T979] async_run_entry_fn+0x39/0x160
> [ 253.444853][ T979] process_one_work+0x24c/0x490