1 files changed, 75 insertions, 2 deletions

diff --git a/kernel/trace/trace_events_user.c b/kernel/trace/trace_events_user.c
index 70d428c394b6..3a2b46847c8b 100644
--- a/kernel/trace/trace_events_user.c
+++ b/kernel/trace/trace_events_user.c
@@ -1990,6 +1990,80 @@ static int user_event_set_tp_name(struct user_event *user)
 }
 
 /*
+ * Counts how many ';' without a trailing space are in the args.
+ */
+static int count_semis_no_space(char *args)
+{
+	int count = 0;
+
+	while ((args = strchr(args, ';'))) {
+		args++;
+
+		if (!isspace(*args))
+			count++;
+	}
+
+	return count;
+}
+
+/*
+ * Copies the arguments while ensuring all ';' have a trailing space.
+ */
+static char *insert_space_after_semis(char *args, int count)
+{
+	char *fixed, *pos;
+	int len;
+
+	len = strlen(args) + count;
+	fixed = kmalloc(len + 1, GFP_KERNEL);
+
+	if (!fixed)
+		return NULL;
+
+	pos = fixed;
+
+	/* Insert a space after ';' if there is no trailing space. */
+	while (*args) {
+		*pos = *args++;
+
+		if (*pos++ == ';' && !isspace(*args))
+			*pos++ = ' ';
+	}
+
+	*pos = '\0';
+
+	return fixed;
+}
+
+static char **user_event_argv_split(char *args, int *argc)
+{
+	char **split;
+	char *fixed;
+	int count;
+
+	/* Count how many ';' without a trailing space */
+	count = count_semis_no_space(args);
+
+	/* No fixup is required */
+	if (!count)
+		return argv_split(GFP_KERNEL, args, argc);
+
+	/* We must fixup 'field;field' to 'field; field' */
+	fixed = insert_space_after_semis(args, count);
+
+	if (!fixed)
+		return NULL;
+
+	/* We do a normal split afterwards */
+	split = argv_split(GFP_KERNEL, fixed, argc);
+
+	/* We can free since argv_split makes a copy */
+	kfree(fixed);
+
+	return split;
+}
+
+/*
  * Parses the event name, arguments and flags then registers if successful.
  * The name buffer lifetime is owned by this method for success cases only.
  * Upon success the returned user_event has its ref count increased by 1.
@@ -2012,7 +2086,7 @@ static int user_event_parse(struct user_event_group *group, char *name,
 		return -EPERM;
 
 	if (args) {
-		argv = argv_split(GFP_KERNEL, args, &argc);
+		argv = user_event_argv_split(args, &argc);
 
 		if (!argv)
 			return -ENOMEM;
@@ -2833,7 +2907,6 @@ static struct ctl_table user_event_sysctls[] = {
 		.mode		= 0644,
 		.proc_handler	= set_max_user_events_sysctl,
 	},
-	{}
 };
 
 static int __init trace_events_user_init(void)