[BUGFIX PATCH v3 4/4] selftests/ftrace: Fix multiple kprobe testcase

[Masami Hiramatsu <mhiramat@kernel.org>]

Fix multiple kprobe event testcase to work it correctly.
There are 2 bugfixes.
 - Since `wc -l FILE` returns not only line number but also
   FILE filename, following "if" statement always failed.
   Fix this bug by replacing it with 'cat FILE | wc -l'
 - Since "while do-done loop" block with pipeline becomes a
   subshell, $N local variable is not update outside of
   the loop.
   Fix this bug by using actual target number (256) instead
   of $N.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
---
 .../ftrace/test.d/kprobe/multiple_kprobes.tc       |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/tools/testing/selftests/ftrace/test.d/kprobe/multiple_kprobes.tc b/tools/testing/selftests/ftrace/test.d/kprobe/multiple_kprobes.tc
index 5862eee91e1d..6e3dbe5f96b7 100644
--- a/tools/testing/selftests/ftrace/test.d/kprobe/multiple_kprobes.tc
+++ b/tools/testing/selftests/ftrace/test.d/kprobe/multiple_kprobes.tc
@@ -20,9 +20,9 @@ while read i; do
   test $N -eq 256 && break
 done
 
-L=`wc -l kprobe_events`
-if [ $L -ne $N ]; then
-  echo "The number of kprobes events ($L) is not $N"
+L=`cat kprobe_events | wc -l`
+if [ $L -ne 256 ]; then
+  echo "The number of kprobes events ($L) is not 256"
   exit_fail
 fi