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The add_remove_uprobe test uses readelf -h to obtain the ELF entry
point (e_entry) and passes it directly as the offset to uprobe_events.
However, uprobe_events expects a file offset, not a virtual address.
For PIE binaries, the virtual address happens to equal the file offset
because the first LOAD segment has p_vaddr == p_offset, so the test
works by coincidence. But for non-PIE executables, e_entry is an
absolute virtual address that can far exceed the file size. When the
probe is enabled, uprobe_register() checks offset > i_size_read(inode)
and rejects it with -EINVAL.
Fix this by converting the virtual address to a file offset using the
ELF program headers: scan readelf -lW output for the LOAD segment
containing the entry point, then compute file_offset = e_entry -
p_vaddr + p_offset. For PIE binaries the result is unchanged; for
non-PIE binaries the offset is correctly translated.
The conversion uses only POSIX shell primitives, with no dependency on
gawk or perl.
Link: https://lore.kernel.org/all/20260807081512.2974757-3-qirui.001@bytedance.com/
Fixes: dc4b165855 ("selftests/ftrace: Use readelf to find entry point in uprobe test")
Cc: stable@vger.kernel.org
Signed-off-by: Rui Qi <qirui.001@bytedance.com>
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
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 :)