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[2/3] trace-cmd: Fix double free error when triggers are configured on multiple events

Message ID 20200325140829.184651-3-tz.stoyanov@gmail.com (mailing list archive)
State Accepted
Commit 346b41d6080e684de326cbc3c3acd844b02e0542
Delegated to: Steven Rostedt
Headers show
Series Fix applying triggers to multiple events | expand

Commit Message

Tzvetomir Stoyanov (VMware) March 25, 2020, 2:08 p.m. UTC 
When using trace-cmd "-e sched:* -R ..." command to set triggers to the all events
of given subsystem, trace-cmd fails with a double free error.
The problem is in create_event() function, where the config is expanded to the all
events. The same "event->trigger" pointer is copied to all events. Later, when the
trigger is applied, the update_event() frees this pointer multiple times.

Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com>
---
 tracecmd/trace-record.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/tracecmd/trace-record.c b/tracecmd/trace-record.c
index ec3bcae9..7dbf599a 100644
--- a/tracecmd/trace-record.c
+++ b/tracecmd/trace-record.c
@@ -2702,7 +2702,8 @@  create_event(struct buffer_instance *instance, char *path, struct event_list *ol
 	else
 		free(p);
 
-	if (event->trigger) {
+	if (old_event->trigger) {
+		event->trigger = strdup(old_event->trigger);
 		ret = asprintf(&p, "%s/trigger", path_dirname);
 		if (ret < 0)
 			die("Failed to allocate trigger path for %s", path);
@@ -2883,6 +2884,7 @@  static void expand_event_instance(struct buffer_instance *instance)
 		event = compressed_list;
 		compressed_list = event->next;
 		expand_event(instance, event);
+		free(event->trigger);
 		free(event);
 	}
 }