On Mon, 11 Aug 2025 16:01:09 +0800 Fushuai Wang <wangfush...@baidu.com> wrote:
> Add a WARN_ON check in move_to_next_cpu(). Next_cpu should > never be greater than or equal to nr_cpu_ids. > > Signed-off-by: Fushuai Wang <wangfush...@baidu.com> > --- > kernel/trace/trace_hwlat.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/kernel/trace/trace_hwlat.c b/kernel/trace/trace_hwlat.c > index 2f7b94e98317..5024b0dcdbba 100644 > --- a/kernel/trace/trace_hwlat.c > +++ b/kernel/trace/trace_hwlat.c > @@ -328,7 +328,7 @@ static void move_to_next_cpu(void) > next_cpu = cpumask_next_wrap(raw_smp_processor_id(), current_mask); > cpus_read_unlock(); > > - if (next_cpu >= nr_cpu_ids) /* Shouldn't happen! */ > + if (WARN_ON(next_cpu >= nr_cpu_ids)) /* Shouldn't happen! */ > goto change_mode; Yeah, it shouldn't happen but it doesn't mean we need to add a WARN_ON(). It might even happen if user space is messing with the tracing_cpumask at the same time. It shouldn't happen but it doesn't mean it will not happen. We do not add WARN_ON() for things that could be trigger by user space. -- Steve
