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Pull tracing fixes from Steven Rostedt: - Initialize hash variables in ftrace subops logic The fix that simplified the ftrace subops logic opened a path where some variables could be used without being initialized, and done subtly where the compiler did not catch it. Initialize those variables to the EMPTY_HASH, which is the default hash. - Reinitialize the hash pointers after they are freed Some of the hash pointers in the subop logic were freed but may still be referenced later. To prevent use-after-free bugs, initialize them back to the EMPTY_HASH. - Free the ftrace hashes when they are replaced The fix that simplified the subops logic updated some hash pointers, but left the original hash that they were pointing to where they are no longer used. This caused a memory leak. Free the hashes that are pointed to by the pointers when they are replaced. - Fix size initialization of ftrace direct function hash The ftrace direct function hash used by BPF initialized the hash size incorrectly. It checked the size of items to a hard coded 32, which made the hash bit size of 5. The hash size is supposed to be limited by the bit size of the hash, as the bitmask is allowed to be greater than 5. Rework the size check to first pass the number of elements to fls() and then compare that to FTRACE_HASH_MAX_BITS before allocating the hash. - Fix format output of ftrace_graph_ent_entry event The field depth of the ftrace_graph_ent_entry event is of size 4 but the output showed it as unsigned long and use "%lu". Change it to unsigned int and use "%u" in the print format that is displayed to user space. - Fix the trace event filter on strings Events can be filtered on numbers or string values. The return value checked from strncpy_from_kernel_nofault() and strncpy_from_user_nofault() was used to determine if reading the strings would fault or not. It would return fault if the value was non zero, which is basically meant that it was always considering the read as a fault. - Add selftest to test trace event string filtering In order to catch the breakage of the string filtering, add a self test to make sure that it continues to work. * tag 'trace-v6.15-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: tracing: selftests: Add testing a user string to filters tracing: Fix filter string testing ftrace: Fix type of ftrace_graph_ent_entry.depth ftrace: fix incorrect hash size in register_ftrace_direct() ftrace: Free ftrace hashes after they are replaced in the subops code ftrace: Reinitialize hash to EMPTY_HASH after freeing ftrace: Initialize variables for ftrace_startup/shutdown_subops()
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 :)