selftests/ftrace: Add syntax error test for multiprobe

Add syntax error test cases for multiprobe appending
errors.

Link: http://lkml.kernel.org/r/156095694541.28024.11918630805148623119.stgit@devnote2

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

tools/testing/selftests/ftrace/test.d/functions

@@ -115,7 +115,7 @@ ftrace_errlog_check() { # err-prefix command-with-error-pos-by-^ command-file
     command=$(echo "$2" | tr -d ^)
     echo "Test command: $command"
     echo > error_log
-    (! echo "$command" > "$3" ) 2> /dev/null
+    (! echo "$command" >> "$3" ) 2> /dev/null
     grep "$1: error:" -A 3 error_log
     N=$(tail -n 1 error_log | wc -c)
     # "  Command: " and "^\n" => 13

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

@@ -87,4 +87,14 @@ case $(uname -m) in
     ;;
 esac
 
+# multiprobe errors
+if grep -q "Create/append/" README && grep -q "imm-value" README; then
+echo 'p:kprobes/testevent _do_fork' > kprobe_events
+check_error '^r:kprobes/testevent do_exit'	# DIFF_PROBE_TYPE
+echo 'p:kprobes/testevent _do_fork abcd=\1' > kprobe_events
+check_error 'p:kprobes/testevent _do_fork ^bcd=\1'	# DIFF_ARG_TYPE
+check_error 'p:kprobes/testevent _do_fork ^abcd=\1:u8'	# DIFF_ARG_TYPE
+check_error 'p:kprobes/testevent _do_fork ^abcd=\"foo"'	# DIFF_ARG_TYPE
+fi
+
 exit 0