tracing: fix return value in __ftrace_event_enable_disable for TRACE_REG_UNREGISTER

[ Upstream commit 0c588ac0ca6c22b774d9ad4a6594681fdfa57d9d ]

When __ftrace_event_enable_disable invokes the class callback to
unregister the event, the return value is not reported up to the
caller, hence leading to event unregister failures being silently
ignored.

This patch assigns the ret variable to the invocation of the
event unregister callback, so that its return value is stored
and reported to the caller, and it raises a warning in case
of error.

Link: https://lore.kernel.org/20250321170821.101403-1-gpaoloni@redhat.com
Signed-off-by: Gabriele Paoloni <gpaoloni@redhat.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 958789fe4cef7ff4f0d782cf6c6a6de825ea02d1..77df1e28fa329a5f3f349e743e0ca4a01d59f67d 100644 (file)
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -405,7 +405,9 @@ static int __ftrace_event_enable_disable(struct trace_event_file *file,
                                clear_bit(EVENT_FILE_FL_RECORDED_TGID_BIT, &file->flags);
                        }
 
-                       call->class->reg(call, TRACE_REG_UNREGISTER, file);
+                       ret = call->class->reg(call, TRACE_REG_UNREGISTER, file);
+
+                       WARN_ON_ONCE(ret);
                }
                /* If in SOFT_MODE, just set the SOFT_DISABLE_BIT, else clear it */
                if (file->flags & EVENT_FILE_FL_SOFT_MODE)