Re: [PATCH v4 09/14] selftests: harness: Move teardown conditional into test metadata

[Jason Gunthorpe]

On Thu, Jun 12, 2025 at 04:27:41PM +0200, Thomas Weißschuh wrote:

> If the assumption is that this is most likely a kernel bug,
> shouldn't it be fixed properly rather than worked around?
> After all the job of a selftest is to detect bugs to be fixed.

I investigated the history for a bit and it seems likely we cannot
change the kernel here. Call it an undocumented "feature".

MAP_HUGETLBFS rounds up the length to some value, userspace has to
figure that out and not pass incorrect lengths.  The selftest is doing
that wrong.

> If the test is broken on ARM64 64k in general then I am also wondering how
> it didn't fail before my change to the selftest harness.

It got lucky and didn't overmap something important.

Jason