On 6/24/21 11:39 PM, Steven Rostedt wrote: > On Tue, 22 Jun 2021 16:42:30 +0200 > Daniel Bristot de Oliveira <bristot@xxxxxxxxxx> wrote: > >> diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c >> index 52fc9438b7b4..c14f33db147e 100644 >> --- a/kernel/trace/trace.c >> +++ b/kernel/trace/trace.c >> @@ -5053,7 +5053,13 @@ int tracing_set_cpumask(struct trace_array *tr, >> arch_spin_unlock(&tr->max_lock); >> local_irq_enable(); >> >> + /* >> + * tracing_cpumask is read by tracers that support CPU >> + * hotplug. >> + */ >> + get_online_cpus(); >> cpumask_copy(tr->tracing_cpumask, tracing_cpumask_new); >> + put_online_cpus(); >> >> return 0; > > Hmm, the tracing_cpumask is only touched in he work function, with the > necessary locks. How is get_online_cpus() protecting it here? > > That is, tracing_cpumask isn't touched in the path of bringing up or > taking down a CPU, and shouldn't be an issue here. You are right, it is not needed with the new hotplug method. > Should I just drop this patch? Yes! drop it. Thanks Steven! -- Daniel > > -- Steve >
