tracing/selftests: Fix kprobe event name test for .isra. functions

commit 23a4b108accc29a6125ed14de4a044689ffeda78 upstream.

The kprobe_eventname.tc test checks if a function with .isra. can have a
kprobe attached to it. It loops through the kallsyms file for all the
functions that have the .isra. name, and checks if it exists in the
available_filter_functions file, and if it does, it uses it to attach a
kprobe to it.

The issue is that kprobes can not attach to functions that are listed more
than once in available_filter_functions. With the latest kernel, the
function that is found is: rapl_event_update.isra.0

  # grep rapl_event_update.isra.0 /sys/kernel/tracing/available_filter_functions
  rapl_event_update.isra.0
  rapl_event_update.isra.0

It is listed twice. This causes the attached kprobe to it to fail which in
turn fails the test. Instead of just picking the function function that is
found in available_filter_functions, pick the first one that is listed
only once in available_filter_functions.

Cc: stable@vger.kernel.org
Fixes: 604e3548236d ("selftests/ftrace: Select an existing function in kprobe_eventname test")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_eventname.tc b/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_eventname.tc
index 3ff236719b6e87891d42ef4f27fb585d21ad9ca3..c50677721a2edbb2003dcf52b48621fe85340e21 100644 (file)
--- a/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_eventname.tc
+++ b/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_eventname.tc
@@ -31,7 +31,8 @@ find_dot_func() {
        fi
 
        grep " [tT] .*\.isra\..*" /proc/kallsyms | cut -f 3 -d " " | while read f; do
-               if grep -s $f available_filter_functions; then
+               cnt=`grep -s $f available_filter_functions | wc -l`;
+               if [ $cnt -eq 1 ]; then
                        echo $f
                        break
                fi