Files
linux/tools/testing/selftests/ftrace
Martin Kaiser 6e3abef2a2 selftests/ftrace: refactor eprobes test to fix argument checks
The add/remove eprobe test installs an eprobe for the openat syscall and
runs ls. It checks the filenames that were opened by ls against a
whitelist and a blacklist.

Commit 206b25c090 ("tracing: eprobe: read the complete FILTER_PTR_STRING
pointer") fixed access to some string fields in eprobes. This triggers
test failures as the blacklist does not allow relative paths for the
openat parameters.

What makes this test unstable is the fact that the openat calls vary a
lot between different systems.

Refactor the test to make it more robust. "cd <directory>" will issue a
chdir syscall with the target directory as parameter. Set an eprobe on
the sys_enter_chdir event and filter for the exact directory name. Allow
(fault) as fallback.

Link: https://lore.kernel.org/all/20260804194705.760893-1-martin@kaiser.cx/

Fixes: 206b25c090 ("tracing: eprobe: read the complete FILTER_PTR_STRING pointer")
Reported-by: kernel test robot <oliver.sang@intel.com>
Closes: https://lore.kernel.org/oe-lkp/202607151010.b68428e1-lkp@intel.com
Signed-off-by: Martin Kaiser <martin@kaiser.cx>
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
2026-08-05 09:01:48 +09:00
..

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 :)