Hi, After reading arch/x86/entry/entry_64.S I think preemption is checked only when returning from interrupt (not exception like syscall) Is is right ? (based on x86) All scenario of checking for preemption in my opinion: (1) check kernel preemption after interrupt https://github.com/torvalds/linux/blob/master/arch/x86/entry/entry_64.S#L672 (2) check user preemption after interrupt https://github.com/torvalds/linux/blob/master/arch/x86/entry/entry_64.S#L620 prepare_exit_to_usermode() -> exit_to_usermode_loop() -> if (cached_flags & _TIF_NEED_RESCHED) schedule(); Thanks, Taeung