Re: [PATCH 5.15 000/159] 5.15.116-rc1 review

[Guenter Roeck]

Hi,

On 6/10/23 12:23, Pavel Machek wrote:
> Hi!
>
> > > Build results:
> > > 	total: 155 pass: 155 fail: 0
> > > Qemu test results:
> > > 	total: 499 pass: 498 fail: 1
> > > Failed tests:
> > > 	arm:kudo-bmc:multi_v7_defconfig:npcm:usb0.1:nuvoton-npcm730-kudo:rootfs
> > >
> > > The test failure is spurious and not new. I observe it randomly on
> > > multi_v7_defconfig builds, primarily on npcm platforms. There is no error
> > > message, just a stalled boot. I have been trying to bisect for a while,
> > > but I have not been successful so far. No immediate concern; I just wanted
> > > to mention it in case someone else hits the same or a similar problem.
> >
> > I managed to revise my bisect script sufficiently enough to get reliable
> > results. It looks like the culprit is commit 503e554782c9 (" debugobject:
> > Ensure pool refill (again)"); see bisect log below. Bisect on four
> > different systems all have the same result. After reverting this patch,
> > I do not see the problem anymore (again, confirmed on four different
> > systems). If anyone has an idea how to debug this, please let me know.
> > I'll be happy to give it a try.
>
> You may want to comment out debug_objects_fill_pool() in
> debug_object_activate or debug_object_assert_init to see which one is
> causing the failure...
>
> CONFIG_PREEMPT_RT is disabled for you, right? (Should 5.15 even have
> that option?)

CONFIG_PREEMPT_RT is disabled (it depends on ARCH_SUPPORTS_RT which is not
enabled by any architecture in v5.15.y).

The added call in debug_object_activate() triggers the problem.
Any idea what to do about it or how to debug it further ?

Thanks,
Guenter