Re: Bug in Kernel 6.8.x, 6.9.x Causing Trace/Panic During Shutdown/Reboot

[Steven Rostedt]

On Fri, 24 May 2024 12:50:08 +0200
"Linux regression tracking (Thorsten Leemhuis)" <regressions@xxxxxxxxxxxxx> wrote:

> [CCing a few people]
> 

Thanks for the Cc.

> On 24.05.24 12:31, Ilkka Naulapää wrote:
> > 
> > I have encountered a critical bug in the Linux vanilla kernel that
> > leads to a kernel panic during the shutdown or reboot process. The
> > issue arises after all services, including `journald`, have been
> > stopped. As a result, the machine fails to complete the shutdown or
> > reboot procedure, effectively causing the system to hang and not shut
> > down or reboot.  

To understand this, did you do anything with tracing? Before shutting down,
is there anything in /sys/kernel/tracing/instances directory?
Were any of the files/directories permissions in /sys/kernel/tracing changed?

> 
> Thx for the report. Not my area of expertise, so take this with a gain
> of salt. But given the versions your mention in your report and the
> screenshot that mentioned tracefs_free_inode I suspect this is caused by
> baa23a8d4360d ("tracefs: Reset permissions on remount if permissions are
> options"). A few fixes for it will soon hit mainline and are meant to be
> backported to affected stable trees:
> 
> https://lore.kernel.org/all/20240523212406.254317554@xxxxxxxxxxx/
> https://lore.kernel.org/all/20240523174419.1e5885a5@xxxxxxxxxxxxxxxxxx/
> 
> You might want to try them – or recheck once they hit the stable trees
> you are about. If they don't work, please report back.

There's been quite a bit of updates in this code, but this looks new to me.
I have more fixes that were just pulled by Linus today.

  https://git.kernel.org/torvalds/c/0eb03c7e8e2a4cc3653eb5eeb2d2001182071215

I'm not sure how relevant that is for this. But if you can reproduce it
with that commit, then this is a new bug.

-- Steve