tracing: Fix synthetic event to accept unsigned modifier

Fix synthetic event to accept unsigned modifier for its field type
correctly.

Currently, synthetic_events interface returns error for "unsigned"
modifiers as below;

 # echo "myevent unsigned long var" >> synthetic_events
 sh: write error: Invalid argument

This is because argv_split() breaks "unsigned long" into "unsigned"
and "long", but parse_synth_field() doesn't expected it.

With this fix, synthetic_events can handle the "unsigned long"
correctly like as below;

 # echo "myevent unsigned long var" >> synthetic_events
 # cat synthetic_events
 myevent	unsigned long var

Link: http://lkml.kernel.org/r/153986832571.18251.8448135724590496531.stgit@devbox
Cc: Shuah Khan <shuah@kernel.org>
Cc: Tom Zanussi <tom.zanussi@linux.intel.com>
Cc: stable@vger.kernel.org
Fixes: commit 4b147936fa50 ("tracing: Add support for 'synthetic' events")
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
index 85f6b01..6ff8394 100644 (file)
--- a/kernel/trace/trace_events_hist.c
+++ b/kernel/trace/trace_events_hist.c
@@ -738,16 +738,30 @@ static void free_synth_field(struct synth_field *field)
        kfree(field);
 }
 
-static struct synth_field *parse_synth_field(char *field_type,
-                                            char *field_name)
+static struct synth_field *parse_synth_field(int argc, char **argv,
+                                            int *consumed)
 {
        struct synth_field *field;
+       const char *prefix = NULL;
+       char *field_type = argv[0], *field_name;
        int len, ret = 0;
        char *array;
 
        if (field_type[0] == ';')
                field_type++;
 
+       if (!strcmp(field_type, "unsigned")) {
+               if (argc < 3)
+                       return ERR_PTR(-EINVAL);
+               prefix = "unsigned ";
+               field_type = argv[1];
+               field_name = argv[2];
+               *consumed = 3;
+       } else {
+               field_name = argv[1];
+               *consumed = 2;
+       }
+
        len = strlen(field_name);
        if (field_name[len - 1] == ';')
                field_name[len - 1] = '\0';
@@ -760,11 +774,15 @@ static struct synth_field *parse_synth_field(char *field_type,
        array = strchr(field_name, '[');
        if (array)
                len += strlen(array);
+       if (prefix)
+               len += strlen(prefix);
        field->type = kzalloc(len, GFP_KERNEL);
        if (!field->type) {
                ret = -ENOMEM;
                goto free;
        }
+       if (prefix)
+               strcat(field->type, prefix);
        strcat(field->type, field_type);
        if (array) {
                strcat(field->type, array);
@@ -1009,7 +1027,7 @@ static int create_synth_event(int argc, char **argv)
        struct synth_field *field, *fields[SYNTH_FIELDS_MAX];
        struct synth_event *event = NULL;
        bool delete_event = false;
-       int i, n_fields = 0, ret = 0;
+       int i, consumed = 0, n_fields = 0, ret = 0;
        char *name;
 
        mutex_lock(&synth_event_mutex);
@@ -1061,13 +1079,13 @@ static int create_synth_event(int argc, char **argv)
                        goto err;
                }
 
-               field = parse_synth_field(argv[i], argv[i + 1]);
+               field = parse_synth_field(argc - i, &argv[i], &consumed);
                if (IS_ERR(field)) {
                        ret = PTR_ERR(field);
                        goto err;
                }
-               fields[n_fields] = field;
-               i++; n_fields++;
+               fields[n_fields++] = field;
+               i += consumed - 1;
        }
 
        if (i < argc) {