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

[Ilkka Naulapää]

Hi Steven,

I took some time and bisected the 6.8.9 - 6.8.10 and git gave the
panic inducing commit:

414fb08628143 (tracefs: Reset permissions on remount if permissions are options)

I reverted that commit to 6.9.2 and now it only serves the trace but
the panic is gone. But I can live with it.

--Ilkka

On Sun, May 26, 2024 at 8:42 PM Ilkka Naulapää <digirigawa@xxxxxxxxx> wrote:
>
> hi,
>
> I took 6.9.2 and applied that 0bcfd9aa4dafa to it. Now the kernel is
> serving me both problems; the trace and the panic as the pic shows.
>
> > 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?
>
> And to answer your question, I did not do any tracing or so and the
> /sys/kernel/tracing is empty.
> Just plain boot-up, no matter if in full desktop or in bare rescue
> mode, ends up the same way.
>
> --Ilkka
>
> On Fri, May 24, 2024 at 8:19 PM Steven Rostedt <rostedt@xxxxxxxxxxx> wrote:
> >
> > On Fri, 24 May 2024 12:50:08 +0200
> > "Linux regression tracking (Thorsten Leemhuis)" <regressions@xxxxxxxxxxxxx> wrote:
> >
> > > > - Affected Versions: Before kernel version 6.8.10, the bug caused a
> > > > quick display of a kernel trace dump before the shutdown/reboot
> > > > completed. Starting from version 6.8.10 and continuing into version
> > > > 6.9.0 and 6.9.1, this issue has escalated to a kernel panic,
> > > > preventing the shutdown or reboot from completing and leaving the
> > > > machine stuck.
> >
> > Ah, I bet it was this commit: baa23a8d4360d ("tracefs: Reset permissions on
> > remount if permissions are options"), which added a "iput" callback to the
> > dentry without calling iput, leaving stale inodes around.
> >
> > This is fixed with:
> >
> >   0bcfd9aa4dafa ("tracefs: Clear EVENT_INODE flag in tracefs_drop_inode()")
> >
> > Try adding just that patch. It will at least make it go back to what was
> > happening before 6.8.10 (I hope!).
> >
> > -- Steve