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selftests/ftrace: Select an existing function in kprobe_eventname test

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Running the ftrace selftests on the latest kernel caused the
kprobe_eventname test to fail. It was due to the test that searches for
a function with at "dot" in the name and adding a probe to that.
Unfortunately, for this test, it picked:

 optimize_nops.isra.2.cold.4

Which happens to be marked as "__init", which means it no longer exists
in the kernel! (kallsyms keeps those function names around for tracing
purposes)

As only functions that still exist are in the
available_filter_functions file, as they are removed when the functions
are freed at boot or module exit, have the test search for a function
with ".isra." in the name as well as being in the
available_filter_functions (if the file exists).

Link: http://lkml.kernel.org/r/20190322150923.1b58eca5@gandalf.local.home

Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
This commit is contained in:
Steven Rostedt (VMware) 2019-03-22 15:09:23 -04:00
parent d59fae6fea
commit 604e354823
1 changed files with 15 additions and 1 deletions
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16
tools/testing/selftests/ftrace/test.d/kprobe/kprobe_eventname.tc
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@ -24,7 +24,21 @@ test -d events/kprobes2/event2 || exit_failure
:;: "Add an event on dot function without name" ;:
FUNC=`grep -m 10 " [tT] .*\.isra\..*$" /proc/kallsyms | tail -n 1 | cut -f 3 -d " "`
find_dot_func() {
if [ ! -f available_filter_functions ]; then
grep -m 10 " [tT] .*\.isra\..*$" /proc/kallsyms | tail -n 1 | cut -f 3 -d " "
return;
fi
grep " [tT] .*\.isra\..*" /proc/kallsyms | cut -f 3 -d " " | while read f; do
if grep -s $f available_filter_functions; then
echo $f
break
fi
done
}
FUNC=`find_dot_func | tail -n 1`
[ "x" != "x$FUNC" ] || exit_unresolved
echo "p $FUNC" > kprobe_events
EVENT=`grep $FUNC kprobe_events | cut -f 1 -d " " | cut -f 2 -d:`