Re: [PATCH 6/9] selftests/damon/sysfs.py: stop obsolete_target shells hanging the test

[sashiko-bot@kernel.org]

> From: Jaeyeon Lee <jaeyeon.lee.dev@gmail.com>
> 
> The obsolete_target test spawns three 'sh' processes as monitoring
> targets.  The processes inherit stdin from the test.  When the test is
> run via 'make run_tests' from an interactive terminal, the kselftest
> runner executes it under 'timeout', which puts it in a background
> process group.  The 'sh' processes then try to read the terminal, so
> the kernel sends SIGTTIN to the whole process group.  This stops the
> 'sh' processes, and also the child the test has just forked to spawn
> the next 'sh', before it can run 'sh'.  The test then waits on that
> child forever, until the kselftest runner kills it after 45 seconds.
> The test passes when run directly.
> 
> Fix this by passing stdin=subprocess.PIPE when spawning the processes.
> The processes then read from a pipe that never receives input, so they
> stay alive and idle as the test expects.
> 
> Assisted-by: LLM
> Signed-off-by: Jaeyeon Lee <jaeyeon.lee.dev@gmail.com>
> Reviewed-by: SJ Park <sj@kernel.org>
> Tested-by: Aveline Noir <jm5905938@gmail.com>
> Signed-off-by: SJ Park <sj@kernel.org>

Sashiko has reviewed this patch and found no issues.

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