tracing: Don't dereference trace_event_file in deferred trigger free

The enable_event trigger defers trace_event_put_ref() to the
trigger free kthread, but the trace_event_file can already be freed
when the instance is removed.

Keep the trace_event_call directly in enable_trigger_data so the
deferred free does not access the freed trace_event_file.

Cc: stable@vger.kernel.org
Fixes: e091351b38 ("tracing: Delay module ref count for "enable_event" trigger")
Reported-by: Alexander Gordeev <agordeev@linux.ibm.com>
Closes: https://lore.kernel.org/all/20260828134340.2501683A24-agordeev@linux.ibm.com/
Link: https://patch.msgid.link/20260911155650.354844-1-aliamemis@disroot.org
Signed-off-by: Ali Ahmet Memiş <aliamemis@disroot.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This commit is contained in:
Ali Ahmet Memiş
2026-09-12 13:27:41 -04:00
committed by Steven Rostedt
parent b4dcc18b97
commit bcfe2816e6
2 changed files with 4 additions and 1 deletions
+1
View File
@@ -1953,6 +1953,7 @@ struct event_trigger_data {
struct enable_trigger_data { struct enable_trigger_data {
struct trace_event_file *file; struct trace_event_file *file;
struct trace_event_call *call;
bool enable; bool enable;
bool hist; bool hist;
}; };
+3 -1
View File
@@ -1728,7 +1728,8 @@ static void enable_trigger_private_data_free(struct event_trigger_data *data)
{ {
struct enable_trigger_data *enable_data = data->private_data; struct enable_trigger_data *enable_data = data->private_data;
trace_event_put_ref(enable_data->file->event_call); /* The file may already be freed here, only the call is kept alive */
trace_event_put_ref(enable_data->call);
kfree(enable_data); kfree(enable_data);
} }
@@ -1801,6 +1802,7 @@ int event_enable_trigger_parse(struct event_command *cmd_ops,
enable_data->hist = hist; enable_data->hist = hist;
enable_data->enable = enable; enable_data->enable = enable;
enable_data->file = event_enable_file; enable_data->file = event_enable_file;
enable_data->call = event_enable_file->event_call;
trigger_data = trigger_data_alloc(cmd_ops, cmd, param, enable_data); trigger_data = trigger_data_alloc(cmd_ops, cmd, param, enable_data);
if (!trigger_data) if (!trigger_data)