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

From: Michael Ellerman <[email-masked]>
Date: Thu, 26 Mar 2020 23:06:23 +1100 (AEDT)

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 <[email-masked]>

Applied to powerpc next, thanks.

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

cheers