[PATCH 6.1 035/197] tracing/trigger: Fix to return error if failed to alloc snapshot

Greg Kroah-Hartman
2024-02-20T20:59:47Z

From: Masami Hiramatsu (Google) <mhiramat@kernel.org>

commit 0958b33ef5a04ed91f61cef4760ac412080c4e08 upstream.

Fix register_snapshot_trigger() to return error code if it failed to
allocate a snapshot instead of 0 (success). Unless that, it will register
snapshot trigger without an error.

Link: https://lore.kernel.org/linux-trace-kernel/170622977792.270660.2789298642759362200.stgit@devnote2

Fixes: 0bbe7f719985 ("tracing: Fix the race between registering 'snapshot' event trigger and triggering 'snapshot' operation")
Cc: stable@vger.kernel.org
Cc: Vincent Donnefort <vdonnefort@google.com>
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
kernel/trace/trace_events_trigger.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)

--- a/kernel/trace/trace_events_trigger.c
+++ b/kernel/trace/trace_events_trigger.c
@@ -1455,8 +1455,10 @@ register_snapshot_trigger(char *glob,
struct event_trigger_data *data,
struct trace_event_file *file)
{
- if (tracing_alloc_snapshot_instance(file->tr) != 0)
- return 0;
+ int ret = tracing_alloc_snapshot_instance(file->tr);
+
+ if (ret < 0)
+ return ret;

return register_trigger(glob, data, file);
}