Re: [PATCH] s390x: stsi: regression test for the STSI 3.2.2 count clamp

[Cornelia Huck <cohuck@redhat.com>]

On Mon, Jun 29 2026, Christian Borntraeger <borntraeger@linux.ibm.com> wrote:

> See https://lore.kernel.org/qemu-devel/20260622092035.400959-1-borntraeger@linux.ibm.com/
> for the QEMU fix.

Could now also refer to QEMU commit a57e4612b61d ("s390x/kvm: clamp stsi
3.2.2 size") directly.

> Add a regression test that races STSI 3.2.2 on one CPU against a second CPU
> that continuously forces an out-of-range count value.
> The out of bound access usually crashes/asserts QEMU with any sane
> distribution build of QEMU, so its more or less guest root can kill itself.
> We should test and fix nevertheless.
> Testcase piggybacks on the existing stsi test, so some cases will be
> tested twice. (with smp 1 and smp 2)
>
> Signed-off-by: Christian Borntraeger <borntraeger@linux.ibm.com>
> Cc: Cornelia Huck <cohuck@redhat.com>
> ---
> If wanted we could split this into a separate file or always run the
> test with smp=2 to avoid the duplication

I think it's reasonable to keep this with the other STSI tests.

>
>  s390x/stsi.c        | 76 ++++++++++++++++++++++++++++++++++++++++++++-
>  s390x/unittests.cfg |  9 ++++++
>  2 files changed, 84 insertions(+), 1 deletion(-)
>

FWIW,

Reviewed-by: Cornelia Huck <cohuck@redhat.com>