Re: Current state of the Linux kernel on SPARC
Hi Tony,
On Fri, 2025-08-29 at 00:45 -0700, Tony Rodriguez wrote:
> *7) Regarding the following: Thanks, this is good to know.
>
> "As for Linux, Michael Karcher also actually found a bug in the M7
> copy_{to,from}_user code which might cause the crashes on S7, see:"
>
> https://github.com/karcherm/sparc-cfu-bug-reproducer/commit/62d36f0353bd523c143131b99bd9231116c1e054
>
> 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.
I think you should (cross-)build a custom kernel for your S7 with the patch applied
as kernels without the patch will show all kinds of erratic behavior. Whether the
behavior shows more or less prominently always depends on the kernel configuration
used.
For example, when enabling support for Transparent Huge Pages, the bug is triggered
already when running "apt update" on an UltraSPARC III. I haven't tested on M7/S7/M8
yet as the prices for these are still rather permissive, so we would definitely need
your testing.
So, I would really recommend building a custom kernel with this patch applied:
https://lore.kernel.org/all/20250828130456.2335-1-kernel@mkarcher.dialup.fu-berlin.de/
And then verify your machine runs stable again. If yes, please add your own:
Tested-by: Tony Rodriguez <unixpro1970@gmail.com>,
Thanks,
Adrian
--
.''`. John Paul Adrian Glaubitz
: :' : Debian Developer
`. `' Physicist
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