ACK: [J][SRU][PATCH 0/1] selftests/ftrace: Stop tracing while reading the trace file by default

[Andrea Righi]

On Fri, Nov 24, 2023 at 05:16:09PM +0800, Po-Hsu Lin wrote:
> BugLink: https://bugs.launchpad.net/bugs/2029405
> 
> [Impact]
> On ARM64 systems, tests like subsystem-enable.tc, event-enable.tc,
> event-pid.tc in linux/tools/testing/selftests/ftrace will take too
> much time to run and consequently leads to test timeout.
> 
> The culprit is the `cat` command on the changing trace file.
> 
> [Fix]
> * 25b9513872 selftests/ftrace: Stop tracing while reading the trace
>   file by default
> 
> This patch can be cherry-picked into Jammy. I didn't see this issue in
> our 5.4 kernels. And it's already landed in newer kernels.
> 
> [Test]
> On an ARM64 testing node, apply this patch to the kernel tree and run
> event-pid.tc test in linux/tools/testing/selftests/ftrace with:
> 
>   sudo ./ftracetest -vvv test.d/event/event-pid.tc
> 
> The test should finish within a few minutes.
> 
> [Regression Potential]
> Change limited to testing tools, it should not have any actual impact
> to kernel functions.

Acked-by: Andrea Righi <andrea.righi at canonical.com>