From bcfe2816e6ec46c3f4c58aa4264476665ddb3f69 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Ali=20Ahmet=20Memi=C5=9F?= Date: Fri, 11 Sep 2026 18:56:47 +0300 Subject: tracing: Don't dereference trace_event_file in deferred trigger free MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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: e091351b3881 ("tracing: Delay module ref count for "enable_event" trigger") Reported-by: Alexander Gordeev 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 Signed-off-by: Steven Rostedt --- kernel/trace/trace.h | 1 + kernel/trace/trace_events_trigger.c | 4 +++- 2 files changed, 4 insertions(+), 1 deletion(-) diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index bd3c8f80300f..3749485a7d85 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -1953,6 +1953,7 @@ struct event_trigger_data { struct enable_trigger_data { struct trace_event_file *file; + struct trace_event_call *call; bool enable; bool hist; }; diff --git a/kernel/trace/trace_events_trigger.c b/kernel/trace/trace_events_trigger.c index 149300cc5e8a..4d2fde996c0f 100644 --- a/kernel/trace/trace_events_trigger.c +++ b/kernel/trace/trace_events_trigger.c @@ -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; - 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); } @@ -1801,6 +1802,7 @@ int event_enable_trigger_parse(struct event_command *cmd_ops, enable_data->hist = hist; enable_data->enable = enable; 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); if (!trigger_data) -- cgit v1.2.3