Re: NULL ptr deref in wq_worker_sleeping on 4.19

[Austin Kim]

Is it possible for you to generate kernel patch only with **kernel
log** for 'use-after-free' case?
With kernel log, we only have limited information, so it is hard to
debug 'use-after-free' case with this signature.

For this matter, kernel should be compiled with below config.
CONFIG_SLUB_DEBUG=y
CONFIG_SLUB_DEBUG_ON=y

2019ë 8ì 7ì (ì) ìí 9:56, Thomas Gleixner <tglx@xxxxxxxxxxxxx>ëì ìì:
>
> 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