Support accessing $argN in the return probe events. This will help users to
record entry data in function return (exit) event for simplfing the function
entry/exit information in one event, and record the result values (e.g.
allocated object/initialized object) at function exit.
For example, if we have a function `int init_foo(struct foo *obj, int param)`
sometimes we want to check how `obj` is initialized. In such case, we can
define a new return event like below;
# echo 'r init_foo retval=$retval param=$arg2 field1=+0($arg1)' >> kprobe_events
Thus it records the function parameter `param` and its result `obj->field1`
(the dereference will be done in the function exit timing) value at once.
This also support fprobe, BTF args and'$arg*'. So if CONFIG_DEBUG_INFO_BTF
is enabled, we can trace both function parameters and the return value
by following command.
# echo 'f target_function%return $arg* $retval' >> dynamic_events
Link: https://lore.kernel.org/all/170952365552.229804.224112990211602895.stgit@devnote2/
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
commit 95c104c378 ("tracing: Auto generate event name when creating a
group of events") changed the syntax in the ftrace README file which is
used by the selftests to check what features are support. Adjust the
string to make test_duplicates.tc and trigger-synthetic-eprobe.tc work
again.
Fixes: 95c104c378 ("tracing: Auto generate event name when creating a group of events")
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Acked-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
The original test for adding and removing eprobes used synthetic events
and retrieved the filename from the open system call at the end of the
system call. This would allow it to always be loaded into the page tables
when accessed.
Masami suggested that the test was too complex for just testing add and
remove, so it was changed to test just adding and removing an event probe
on top of the start of the open system call event. Now it is possible that
the filename will not be loaded into memory at the time the eprobe is
triggered, and will result in "(fault)" being displayed in the event. This
causes the test to fail.
Account for "(fault)" also being one of the values of the filename field
of the event probe.
Link: https://lkml.kernel.org/r/20210907230429.5783d519@rorschach.local.home
Fixes: 079db70794 ("selftests/ftrace: Add test case to test adding and removing of event probe")
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Commit cad6967ac1 ("fork: introduce kernel_clone()") replaced "_do_fork()"
with "kernel_clone()". The ftrace selftests reference the fork function in
several of the tests. The rename will make the tests break, but if those
names are changed in the tests, they would then break on older kernels. The
same set of tests should pass older kernels if they have previously passed.
Obviously, a new test may not work on older kernels if the test was added
due to a bug or a new feature.
The setup of ftracetest will now create a $FUNCTION_FORK bash variable
that will contain "_do_fork" for older kernels and "kernel_clone" for newer
ones. It figures out the proper name by examining /proc/kallsyms.
Note, available_filter_functions could also be used, but because some tests
should be able to pass without function tracing enabled, it could not be
used.
Fixes: eea11285da ("tracing: switch to kernel_clone()")
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
Add ":README" suffix support for the requires list, so that
the testcase can list up the required string for README file
to the requires list.
Note that the required string is treated as a fixed string,
instead of regular expression. Also, the testcase can specify
a string containing spaces with quotes. E.g.
# requires: "place: [<module>:]<symbol>":README
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Reviewed-by: Tom Zanussi <zanussi@kernel.org>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
