On Fri, Jun 08, 2018 at 11:52:20AM +0200, Oleg Nesterov wrote: > in smpboot_update_cpumask_percpu_thread() can hit a KTHREAD_SHOULD_PARK > thread? Lets look into kernel test robot's .config: > > CONFIG_NR_CPUS=1 > > Now look at NR_CPUS==1 version of for_each_cpu* helpers: > > #define for_each_cpu(cpu, mask) \ > for ((cpu) = 0; (cpu) < 1; (cpu)++, (void)mask)
Argh, that issue again. > So even if the "tmp" cpumask is empty the code above always does > > smpboot_park_thread(plug_thread, 0); > > and hits the already parked kthread. OK, I'll write a new Changelog.
