Re: [PATCH v3 2/3] selftests/powerpc: Add tm-signal-pagefault test

On Tue, 2020-02-11 at 03:38:30 UTC, Gustavo Luiz Duarte wrote:

This test triggers a TM Bad Thing by raising a signal in transactional state
and forcing a pagefault to happen in kernelspace when the kernel signal
handling code first touches the user signal stack.

This is inspired by the test tm-signal-context-force-tm but uses userfaultfd to
make the test deterministic. While this test always triggers the bug in one
run, I had to execute tm-signal-context-force-tm several times (the test runs
5000 times each execution) to trigger the same bug.

tm-signal-context-force-tm is kept instead of replaced because, while this test
is more reliable and triggers the same bug, tm-signal-context-force-tm has a
better coverage, in the sense that by running the test several times it might
trigger the pagefault and/or be preempted at different places.

v3: skip test if userfaultfd is unavailable.

Signed-off-by: Gustavo Luiz Duarte <redacted>

Applied to powerpc next, thanks.

https://git.kernel.org/powerpc/c/915b7f6f9a5e232c138bb36743a1fdb0fcf2c432

cheers