Merge tag 'trace-v4.18-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

Pull tracing fixes from Steven Rostedt:
 "Various fixes to the tracing infrastructure:

   - Fix double free when the reg() call fails in
     event_trigger_callback()

   - Fix anomoly of snapshot causing tracing_on flag to change

   - Add selftest to test snapshot and tracing_on affecting each other

   - Fix setting of tracepoint flag on error that prevents probes from
     being deleted.

   - Fix another possible double free that is similar to
     event_trigger_callback()

   - Quiet a gcc warning of a false positive unused variable

   - Fix crash of partial exposed task->comm to trace events"

* tag 'trace-v4.18-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  kthread, tracing: Don't expose half-written comm when creating kthreads
  tracing: Quiet gcc warning about maybe unused link variable
  tracing: Fix possible double free in event_enable_trigger_func()
  tracing/kprobes: Fix trace_probe flags on enable_trace_kprobe() failure
  selftests/ftrace: Add snapshot and tracing_on test case
  ring_buffer: tracing: Inherit the tracing setting to next ring buffer
  tracing: Fix double free of event_trigger_data

1 files changed, 13 insertions, 5 deletions

diff --git a/kernel/trace/trace_events_trigger.c b/kernel/trace/trace_events_trigger.c
index d18249683682..5dea177cef53 100644
--- a/kernel/trace/trace_events_trigger.c
+++ b/kernel/trace/trace_events_trigger.c
@@ -679,6 +679,8 @@ event_trigger_callback(struct event_command *cmd_ops,
 		goto out_free;
 
  out_reg:
+	/* Up the trigger_data count to make sure reg doesn't free it on failure */
+	event_trigger_init(trigger_ops, trigger_data);
 	ret = cmd_ops->reg(glob, trigger_ops, trigger_data, file);
 	/*
 	 * The above returns on success the # of functions enabled,
@@ -686,11 +688,13 @@ event_trigger_callback(struct event_command *cmd_ops,
 	 * Consider no functions a failure too.
 	 */
 	if (!ret) {
+		cmd_ops->unreg(glob, trigger_ops, trigger_data, file);
 		ret = -ENOENT;
-		goto out_free;
-	} else if (ret < 0)
-		goto out_free;
-	ret = 0;
+	} else if (ret > 0)
+		ret = 0;
+
+	/* Down the counter of trigger_data or free it if not used anymore */
+	event_trigger_free(trigger_ops, trigger_data);
  out:
 	return ret;
 
@@ -1416,6 +1420,9 @@ int event_enable_trigger_func(struct event_command *cmd_ops,
 		goto out;
 	}
 
+	/* Up the trigger_data count to make sure nothing frees it on failure */
+	event_trigger_init(trigger_ops, trigger_data);
+
 	if (trigger) {
 		number = strsep(&trigger, ":");
 
@@ -1466,6 +1473,7 @@ int event_enable_trigger_func(struct event_command *cmd_ops,
 		goto out_disable;
 	/* Just return zero, not the number of enabled functions */
 	ret = 0;
+	event_trigger_free(trigger_ops, trigger_data);
  out:
 	return ret;
 
@@ -1476,7 +1484,7 @@ int event_enable_trigger_func(struct event_command *cmd_ops,
  out_free:
 	if (cmd_ops->set_filter)
 		cmd_ops->set_filter(NULL, trigger_data, NULL);
-	kfree(trigger_data);
+	event_trigger_free(trigger_ops, trigger_data);
 	kfree(enable_data);
 	goto out;
 }