tracing/kprobes: Reject new event if loc is NULL

Reject the new event which has NULL location for kprobes.
For kprobes, user must specify at least the location.

Link: http://lkml.kernel.org/r/158779376597.6082.1411212055469099461.stgit@devnote2
Cc: Tom Zanussi <zanussi@kernel.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: stable@vger.kernel.org
Fixes: 2a588dd1d5d6 ("tracing: Add kprobe event command generation functions")
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index 0d9300c3b08467f6ac16b4d0743963ebe5c628f3..35989383ae1131e11e45a39e0a5333a57f4493e0 100644 (file)
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -940,6 +940,9 @@ EXPORT_SYMBOL_GPL(kprobe_event_cmd_init);
  * complete command or only the first part of it; in the latter case,
  * kprobe_event_add_fields() can be used to add more fields following this.
  *
+ * Unlikely the synth_event_gen_cmd_start(), @loc must be specified. This
+ * returns -EINVAL if @loc == NULL.
+ *
  * Return: 0 if successful, error otherwise.
  */
 int __kprobe_event_gen_cmd_start(struct dynevent_cmd *cmd, bool kretprobe,
@@ -953,6 +956,9 @@ int __kprobe_event_gen_cmd_start(struct dynevent_cmd *cmd, bool kretprobe,
        if (cmd->type != DYNEVENT_TYPE_KPROBE)
                return -EINVAL;
 
+       if (!loc)
+               return -EINVAL;
+
        if (kretprobe)
                snprintf(buf, MAX_EVENT_NAME_LEN, "r:kprobes/%s", name);
        else