CVE-2026-74471: Undefined Security Weakness

In the Linux kernel, the following vulnerability has been resolved:

tracing: Check return value of __register_event() in trace_module_add_events()

trace_module_add_events() ignores the return value of __register_event() and unconditionally calls __add_event_to_tracers() for each event.

If __register_event() fails (for example, if event_init() fails), the trace_event_call is not added to ftrace_events list, but __add_event_to_tracers() still creates a trace_event_file pointing to it. If module loading subsequently fails and module memory is freed, tracing state retains a stale trace_event_call pointer in trace_event_file, leading to a use-after-free when tracefs or tracing subsystem operations are later executed.

Fix this by checking the return value of __register_event() and only calling __add_event_to_tracers() if event registration succeeded.