On Thu 04-04-19 13:02:19, Dan Carpenter wrote: > There have been two cases recently where we pass user a controlled "cpu" > to possible_cpus(). That's not allowed. If it's invalid, it will > trigger a WARN_ONCE() and an out of bounds read which could result in an > Oops. > > This patch introduces possible_cpu_safe() which first checks to see if > the cpu is valid, turns off speculation and then checks if the cpu is > possible. Why cannot we do the check in possible_cpu directly? Is it used from any hot path? I am quite skeptical people will use the new helper consistently. -- Michal Hocko SUSE Labs
