[SRU][N:linux][PATCH 0/1] Fix false failure of subsystem event test

[Magali Lemes]

BugLink: https://bugs.launchpad.net/bugs/2071861

[Impact]
The ftrace tracing subsystem event test has been failing intermittently in some
instances ever since commit 1a4ea83a6e67 ("selftests/ftrace: Limit length in
subsystem-enable tests") was backported to our trees.

[Fix]
Clean cherry-pick of 213879061a9c ("selftests/tracing: Fix false failure of
subsystem event test").

[Test]
- Launch an AWS c4.large instance running Noble.
- Install the generic 6.8 kernel and boot into it.
- Clone the noble:linux tree and cd to it.
- Go to tools/testing/selftests/ftrace
- Run `sudo ./ftracetest test.d/event/subsystem-enable.tc` a couple of times.
The test is expected to fail.
- Apply this patch and run `sudo ./ftracetest test.d/event/subsystem-enable.tc`
a couple of times again. The test should now always pass.

[Where problems could occur]
Change is limited to the subsystem event test, no problems should occur in the
kernel image or modules.

[Other info]
Jammy was affected but got this fix through upstream stable updates. Questing
already has this fix as it landed in v6.17.

Steven Rostedt (1):
  selftests/tracing: Fix false failure of subsystem event test

 .../ftrace/test.d/event/subsystem-enable.tc   | 28 +++++++++++++++++--
 1 file changed, 26 insertions(+), 2 deletions(-)

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2.34.1