Re: Current state of the Linux kernel on SPARC
On Fri, 2025-08-29 at 08:35 -0400, Dennis Clarke wrote:
> On 8/29/25 03:45, Tony Rodriguez wrote:
> > Regarding my tests:
> >
> > 1) Running non-SMP mode with 6.16.3-1 kernel makes no difference (it
> > still panics in the same fashion using nosmp keyword via grub).
> > Confirmed it was truly running in non-smp mode as well with kernel
> > 6.12.38/6.16.3-1 (which cat /proc/cpuinfo shows).
> >
>
> I see the word "panic" and then stop. Feels like a real problem in the
> Linux kernel these days for the top of the line SPARC hardware.
Not really. Just a kernel bug that got introduced in 2017 and didn't see a fix
until since Oracle stopped working on Linux for SPARC in 2017.
> > 2) Believe the ISO installer is using kernel 6.12.38 during the initial
> > bootup (which at least boots).
> >
> > Note: After ISO installation, if toggled via grub to use 6.12.38 the
> > s7-2 boots practically every time, but there are still plenty of tainted
> > kernel messages during boot-up.
> >
>
> Which may or may not be patched. Furthermore those patches are not in
> the mainline Linux kernel ... or are they ?
They will be upstreamed soonish. Andreas Larsson (the current kernel maintainer
for Linux on SPARC) is aware of them. They just need some more testing, especially
on UltraSPARC I + II, SPARC T1 and SPARC M7/S7/M8.
Do you happen to have a SPARC T1?
> > Typically, only does so when previously booted using a 6.12.38 kernel
> > then rebooted using 6.16.3-1. For kernel 6.16.3-1, often have to select
> > rescue mode or use systemd.unit=multi-user.target via grub as well.
>
> Right. You have a whole layer of unwanted complexity layered on top of
> this kernel problem. Get away from SystemD entirely. Just use a trivial
> OpenRC or sysvinit type of system. You really need Gentoo here. For any
> trivial testing of a kernel issue it is a disaster to use SystemD.
systemd isn't the problem, kernel bugs are. You cannot expect anything to work
reliably if the kernel is corrupting more and more memory while the machine
is running.
> > *4) Also, not ruling out a possible systemd issue, noticed systemd-udevd
> > is launched shortly before 6.16.3-1 panic(s). Seems latest Debian 12 for
> > sparc64 is using systemd-258-rc3-1. There certainly may be systemd
> > related bugs as well.
> >
>
> Remove SystemD from the equation entirely.
Please don't turn this into a systemd circlejerk. That discussion is long settled
and there is no need to open this can of worms again. It's a kernel bug which is
present no matter what init system you're using, so bashing systemd is just moot.
> >
> > 5) Regarding the question: "Thought the current Solaris 11.4 CBE
> > doesn't work on the S7, does it?
> >
> > I reset the S7-2 LDOM/Service Processor back to factory defaults
> > using ILOM CLI/web and an older Solaris 11.4 (11.4.42.113.1), without
> > using the latest Oracle Solaris CBE (11.4.81) version (since it doesn't
> > work on the S7-2). Hopefully, Oracle will resolve this S7-2 Solaris CBE
> > problem soon in a future update.
> >
>
> Do not hold your breath for anything to ever be released by Oracle that
> will work on this hardware. There is no business process to justify the
> expense.
It's hardware that is still officially supported and I'm pretty confident that
the problem has already been fixed in one of the commercial SRUs. The fix will
eventually be released to the CBE version of Solaris.
> > 8) Regarding "please test Michael's patch series on your Linux
> > distribution of choice, be it Gentoo or T2DE and report back!".
> >
> > Understood, want to rule out systemd first and then will try to allocate
> > additional time to research this.
> >
>
> Remove that SystemD from the problem. Here we need to create a custom
> Gentoo bootable ( or similar ) trivial ISO with the bare minimum of
> kernel adjustments and modules. Anything else will just be noise on
> top of a very limited signal.
Non-sense.
Adrian
--
.''`. John Paul Adrian Glaubitz
: :' : Debian Developer
`. `' Physicist
`- GPG: 62FF 8A75 84E0 2956 9546 0006 7426 3B37 F5B5 F913
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