On Fri, Aug 02, 2019 at 08:15:01AM -0700, Paul E. McKenney wrote: > The multi_cpu_stop() function relies on the scheduler to gain control from > whatever is running on the various online CPUs, including any nohz_full > CPUs running long loops in kernel-mode code. Lack of the scheduler-clock > interrupt on such CPUs can delay multi_cpu_stop() for several minutes > and can also result in RCU CPU stall warnings. This commit therefore > causes multi_cpu_stop() to enable the scheduler-clock interrupt on all > online CPUs. This sounds wrong; should we be fixing sched_can_stop_tick() instead to return false when the stop task is runnable?
