Re: 5.10.0-4-sparc64-smp #1 Debian 5.10.19-1 crashes on T2000

[Frank Scheiner <frank.scheiner@web.de>]

Hi Riccardo,

On 11.03.21 23:03, Riccardo Mottola wrote:
> Hi Frank!
>
> I suppose the Niagara CPU gives the kernel issue

From [1] I assume T2 CPUs are not affected, but yeah, the issue could
be that selective that it only affects the very first generation.

[1]: https://lists.debian.org/debian-sparc/2021/03/msg00010.html

> Frank Scheiner wrote:
> > > If I remember there was a repository with many snapshots of different
> > > versions, already as package, which one can test quickly. That way we
> > > can restrict breakage range without git bisect.
> > >
> > > Do you have a link?
> >
> > I assume you mean "http://snapshot.debian.org"; .
>
> Exactly. With this I did some more tests.
>
> Still Works:
> 5.9.0-4-sparc64-smp #1 SMP Debian 5.9.11-1 (2020-11-27)
> 5.9.0-5-sparc64-smp #1 SMP Debian 5.9.15-1 (2020-12-17)
>
> Broken:
>
> linux-image-5.10.0-trunk-sparc64-smp_5.10.2-1~exp1_sparc64.deb
>
> So later series 5.9 series continue to work and even very early 5.10 do not
>
> Do you know if I can via serial-console reset the system?

Reset from the serial console might work via the kernel with the [magic
system request] functionality.

[magic system request]:
https://www.kernel.org/doc/html/v4.11/admin-guide/sysrq.html

But you can always reset the system using the SC. The T1000 (and the
T2000, too) has both serial (on T2000 right of the DB-9 ttya port,
should work with a blue Cisco serial cable) and network port (on T2000
above the two USB ports). The serial port of the SC automatically
switches to the system console after some (configurable) time and you
need to escape to the SC login prompt with a configurable key sequence
(`#.` by default, see [2]).

[2]:
https://docs.oracle.com/cd/E19076-01/t2k.srvr/819-2549-12/ontario-consoleConfig.html#28277

> I tried sending a break on the serial console, but the errors just keep
> running.
> Break is received, since I see it as SC Alert, but I am not put into the
> console, maybe there is some further trick on these newer machine?

So you already got access to the SC. Then you can reset the machine from
there, too.

> I am
> used to old SparcStations and UltraSparc Netras, where it was sufficient.
> It is inconvenient at every hang to power-cycle, since at every turn on,
> it runs a self-test which lasts minutes :)

I think depending on the SC configuration, these machines also run a
self-test for every X resets, but this should be configurable.

Hope that helps
Cheers,
Frank