[for-linus][PATCH 3/7] tracing/user_events: Hold event_mutex during dyn_event_add

Steven Rostedt
2022-04-03T14:31:56Z

From: Beau Belgrave <beaub@linux.microsoft.com>

Make sure the event_mutex is properly held during dyn_event_add call.
This is required when adding dynamic events.

Link: https://lkml.kernel.org/r/20220328223225.1992-1-beaub@linux.microsoft.com

Reported-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Beau Belgrave <beaub@linux.microsoft.com>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
kernel/trace/trace_events_user.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/kernel/trace/trace_events_user.c b/kernel/trace/trace_events_user.c
index 8b3d241a31c2..61d78d64bdf0 100644
--- a/kernel/trace/trace_events_user.c
+++ b/kernel/trace/trace_events_user.c
@@ -1165,11 +1165,11 @@ static int user_event_parse(char *name, char *args, char *flags,
#endif

mutex_lock(&event_mutex);
+
ret = user_event_trace_register(user);
- mutex_unlock(&event_mutex);

if (ret)
- goto put_user;
+ goto put_user_lock;

user->index = index;

@@ -1181,8 +1181,12 @@ static int user_event_parse(char *name, char *args, char *flags,
set_bit(user->index, page_bitmap);
hash_add(register_table, &user->node, key);

+ mutex_unlock(&event_mutex);
+
*newuser = user;
return 0;
+put_user_lock:
+ mutex_unlock(&event_mutex);
put_user:
user_event_destroy_fields(user);
user_event_destroy_validators(user);
--
2.35.1