Re: NULL ptr deref in wq_worker_sleeping on 4.19

From: Thomas Gleixner
Date: Wed Aug 07 2019 - 08:56:15 EST


On Wed, 7 Aug 2019, Austin Kim wrote:

A: Because it messes up the order in which people normally read text.
Q: Why is top-posting such a bad thing?
A: Top-posting.
Q: What is the most annoying thing in e-mail?

A: No.
Q: Should I include quotations after my reply?

http://daringfireball.net/2007/07/on_top

> I wonder what kinds of workqueue is used in case of this panic.
>
> If system workqueue(system_wq) is used for this case, it would be a
> help to replace it with high priority workqueue(system_highpri_wq). If
> panic disappers with high priority workqueue(system_highpri_wq), we
> would think about another scenario.

How would that help? As Sebastian explained, something overwrote memory or
it is a Use After Free. How would a high priority workqueue 'fix' that?

You need to find the root cause, which is either memory corruption or a use
after free.

Thanks,

tglx