1 files changed, 19 insertions, 5 deletions

diff --git a/tools/perf/util/sort.c b/tools/perf/util/sort.c
index b4a805e5e440..1958637cf136 100644
--- a/tools/perf/util/sort.c
+++ b/tools/perf/util/sort.c
@@ -1453,7 +1453,7 @@ static int __setup_sorting(void)
         int ret = 0;
 
         if (sort_keys == NULL) {
-                if (field_order) {
+                if (is_strict_order(field_order)) {
                         /*
                          * If user specified field order but no sort order,
                          * we'll honor it and not add default sort orders.
@@ -1639,23 +1639,36 @@ static void reset_dimensions(void)
                 memory_sort_dimensions[i].taken = 0;
 }
 
+bool is_strict_order(const char *order)
+{
+        return order && (*order != '+');
+}
+
 static int __setup_output_field(void)
 {
-        char *tmp, *tok, *str;
-        int ret = 0;
+        char *tmp, *tok, *str, *strp;
+        int ret = -EINVAL;
 
         if (field_order == NULL)
                 return 0;
 
         reset_dimensions();
 
-        str = strdup(field_order);
+        strp = str = strdup(field_order);
         if (str == NULL) {
                 error("Not enough memory to setup output fields");
                 return -ENOMEM;
         }
 
-        for (tok = strtok_r(str, ", ", &tmp);
+        if (!is_strict_order(field_order))
+                strp++;
+
+        if (!strlen(strp)) {
+                error("Invalid --fields key: `+'");
+                goto out;
+        }
+
+        for (tok = strtok_r(strp, ", ", &tmp);
                         tok; tok = strtok_r(NULL, ", ", &tmp)) {
                 ret = output_field_add(tok);
                 if (ret == -EINVAL) {
@@ -1667,6 +1680,7 @@ static int __setup_output_field(void)
                 }
         }
 
+out:
         free(str);
         return ret;
 }