On Tue, Oct 12, 2021 at 01:40:31PM +0800, 王贇 wrote: > diff --git a/kernel/trace/trace_event_perf.c b/kernel/trace/trace_event_perf.c > index 6aed10e..33c2f76 100644 > --- a/kernel/trace/trace_event_perf.c > +++ b/kernel/trace/trace_event_perf.c > @@ -441,12 +441,19 @@ void perf_trace_buf_update(void *record, u16 type) > if (!rcu_is_watching()) > return; > > + /* > + * Prevent CPU changing from now on. rcu must > + * be in watching if the task was migrated and > + * scheduled. > + */ > + preempt_disable_notrace(); > + > if ((unsigned long)ops->private != smp_processor_id()) > - return; > + goto out; > > bit = ftrace_test_recursion_trylock(ip, parent_ip); > if (bit < 0) > - return; > + goto out; > > event = container_of(ops, struct perf_event, ftrace_ops); >
This seems rather daft, wouldn't it be easier to just put that check under the recursion thing?
