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mirror of https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git synced 2026-01-18 04:20:44 +00:00
Steven Rostedt dd4adb986a selftests/tracing: Run sample events to clear page cache events
The tracing selftest "event-filter-function.tc" was failing because it
first runs the "sample_events" function that triggers the kmem_cache_free
event and it looks at what function was used during a call to "ls".

But the first time it calls this, it could trigger events that are used to
pull pages into the page cache.

The rest of the test uses the function it finds during that call to see if
it will be called in subsequent "sample_events" calls. But if there's no
need to pull pages into the page cache, it will not trigger that function
and the test will fail.

Call the "sample_events" twice to trigger all the page cache work before
it calls it to find a function to use in subsequent checks.

Cc: stable@vger.kernel.org
Fixes: eb50d0f250e96 ("selftests/ftrace: Choose target function for filter test from samples")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
2025-11-10 18:00:07 -07:00
..

Linux Ftrace Testcases

This is a collection of testcases for ftrace tracing feature in the Linux
kernel. Since ftrace exports interfaces via the debugfs, we just need
shell scripts for testing. Feel free to add new test cases.

Running the ftrace testcases
============================

At first, you need to be the root user to run this script.
To run all testcases:

  $ sudo ./ftracetest

To run specific testcases:

  # ./ftracetest test.d/basic3.tc

Or you can also run testcases under given directory:

  # ./ftracetest test.d/kprobe/

Contributing new testcases
==========================

Copy test.d/template to your testcase (whose filename must have *.tc
extension) and rewrite the test description line.

 * The working directory of the script is <debugfs>/tracing/.

 * Take care with side effects as the tests are run with root privilege.

 * The tests should not run for a long period of time (more than 1 min.)
   These are to be unit tests.

 * You can add a directory for your testcases under test.d/ if needed.

 * The test cases should run on dash (busybox shell) for testing on
   minimal cross-build environments.

 * Note that the tests are run with "set -e" (errexit) option. If any
   command fails, the test will be terminated immediately.

 * The tests can return some result codes instead of pass or fail by
   using exit_unresolved, exit_untested, exit_unsupported and exit_xfail.

Result code
===========

Ftracetest supports following result codes.

 * PASS: The test succeeded as expected. The test which exits with 0 is
         counted as passed test.

 * FAIL: The test failed, but was expected to succeed. The test which exits
         with !0 is counted as failed test.

 * UNRESOLVED: The test produced unclear or intermidiate results.
             for example, the test was interrupted
                       or the test depends on a previous test, which failed.
                       or the test was set up incorrectly
             The test which is in above situation, must call exit_unresolved.

 * UNTESTED: The test was not run, currently just a placeholder.
             In this case, the test must call exit_untested.

 * UNSUPPORTED: The test failed because of lack of feature.
               In this case, the test must call exit_unsupported.

 * XFAIL: The test failed, and was expected to fail.
          To return XFAIL, call exit_xfail from the test.

There are some sample test scripts for result code under samples/.
You can also run samples as below:

  # ./ftracetest samples/

TODO
====

 * Fancy colored output :)