Re: [Syzkaller & bisect] There is INFO: task hung in __rq_qos_throttle

From: Kent Overstreet
Date: Wed Oct 23 2024 - 21:58:10 EST


On Mon, Oct 21, 2024 at 06:27:25PM +0800, Lai, Yi wrote:
> Hi Kent Overstreet,
>
> Greetings!
>
> I used Syzkaller and found that there is INFO: task hung in __rq_qos_throttle in v6.12-rc2
>
> After bisection and the first bad commit is:
> "
> 63332394c7e1 bcachefs: Move snapshot table size to struct snapshot_table

You sure...?

Look at the patch, that's a pretty unlikely culprit; we would've seen
something from kasan, and anyways there's guards on the new memory
accesses/array derefs.

I've been seeing that bug too, but it's very intermittent. How did you
get it to trigger reliably enough for a bisect?