selftests/powerpc: Test for spurious kernel memory faults on radix

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Previously when mapping kernel memory on radix, no ptesync was
included which would periodically lead to unhandled spurious faults.
Mapping kernel memory is used when code patching with Strict RWX
enabled. As suggested by Chris Riedl, turning ftrace on and off does a
large amount of code patching so is a convenient way to see this kind
of fault.

Add a selftest to try and trigger this kind of a spurious fault. It
tests for 30 seconds which is usually long enough for the issue to
show up.

Signed-off-by: Jordan Niethe <jniethe5@gmail.com>
[mpe: Rename it to better reflect what it does, rather than the symptom]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210208032957.1232102-2-jniethe5@gmail.com

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Jordan Niethe 2021-02-08 14:29:57 +11:00 • committed by Michael Ellerman

parent b8b2f37cf6

commit 29e3ea8cbd

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tools/testing/selftests/powerpc/mm/Makefile

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tools/testing/selftests/powerpc/mm/stress_code_patching.sh Executable file

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