tracing: Add new testcases for hist trigger parsing errors

Add a testcase ensuring that the tracing error_log correctly displays
hist trigger parsing errors.

Link: http://lkml.kernel.org/r/62ec58d9aca661cde46ba678e32a938427945e9e.1561743018.git.zanussi@kernel.orgReviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Tom Zanussi <zanussi@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

tools/testing/selftests/ftrace/test.d/trigger/trigger-hist-syntax-errors.tc

+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+# description: event trigger - test histogram parser errors
+
+if [ ! -f set_event -o ! -d events/kmem ]; then
+    echo "event tracing is not supported"
+    exit_unsupported
+fi
+
+if [ ! -f events/kmem/kmalloc/trigger ]; then
+    echo "event trigger is not supported"
+    exit_unsupported
+fi
+
+if [ ! -f events/kmem/kmalloc/hist ]; then
+    echo "hist trigger is not supported"
+    exit_unsupported
+fi
+
+[ -f error_log ] || exit_unsupported
+
+check_error() { # command-with-error-pos-by-^
+    ftrace_errlog_check 'hist:kmem:kmalloc' "$1" 'events/kmem/kmalloc/trigger'
+}
+
+check_error 'hist:keys=common_pid:vals=bytes_req:sort=common_pid,^junk'	# INVALID_SORT_FIELD
+check_error 'hist:keys=common_pid:vals=bytes_req:^sort='		# EMPTY_ASSIGNMENT
+check_error 'hist:keys=common_pid:vals=bytes_req:^sort=common_pid,'	# EMPTY_SORT_FIELD
+check_error 'hist:keys=common_pid:vals=bytes_req:sort=common_pid.^junk'	# INVALID_SORT_MODIFIER
+check_error 'hist:keys=common_pid:vals=bytes_req,bytes_alloc:^sort=common_pid,bytes_req,bytes_alloc'	# TOO_MANY_SORT_FIELDS
+
+exit 0