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

[Tim Whisonant]

On Thu, Dec 04, 2025 at 04:53:19PM -0300, Magali Lemes wrote:
> 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(-)
> 
> -- 
> 2.34.1
> 
 
Acked-by: Tim Whisonant <tim.whisonant at canonical.com>