selftests/ftrace: Add a test to probe module functions

Add a kprobes test to ensure that we are able to add a probe on a
module function using 'p <mod>:<func>' format, with/without having to
specify a probe name.

Link: http://lkml.kernel.org/r/2d8087e25a7ad9206f3e2b7b4bb0c3c86eaa38af.1499453040.git.naveen.n.rao@linux.vnet.ibm.comSuggested-by: Masami Hiramatsu <mhiramat@kernel.org>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

tools/testing/selftests/ftrace/test.d/kprobe/kprobe_module.tc

+#!/bin/sh
+# description: Kprobe dynamic event - probing module
+
+[ -f kprobe_events ] || exit_unsupported # this is configurable
+
+disable_events
+echo > kprobe_events
+
+:;: "Add an event on a module function without specifying event name" ;:
+
+MOD=`lsmod | head -n 2 | tail -n 1 | cut -f1 -d" "`
+FUNC=`grep -m 1 ".* t .*\\[$MOD\\]" /proc/kallsyms | xargs | cut -f3 -d" "`
+[ "x" != "x$MOD" -a "y" != "y$FUNC" ] || exit_unresolved
+echo "p $MOD:$FUNC" > kprobe_events
+PROBE_NAME=`echo $MOD:$FUNC | tr ".:" "_"`
+test -d events/kprobes/p_${PROBE_NAME}_0 || exit_failure
+
+:;: "Add an event on a module function with new event name" ;:
+
+echo "p:event1 $MOD:$FUNC" > kprobe_events
+test -d events/kprobes/event1 || exit_failure
+
+:;: "Add an event on a module function with new event and group name" ;:
+
+echo "p:kprobes1/event1 $MOD:$FUNC" > kprobe_events
+test -d events/kprobes1/event1 || exit_failure
+
+echo > kprobe_events