Hi Gregory, I'll try to read this series next Monday, I need to recall what does syscall-user-dispatch actually do ;) just one question for now, On 01/20, Gregory Price wrote: > > --- a/kernel/ptrace.c > +++ b/kernel/ptrace.c > @@ -370,6 +370,10 @@ static int check_ptrace_options(unsigned long data) > if (data & ~(unsigned long)PTRACE_O_MASK) > return -EINVAL; > > + if (unlikely(data & PTRACE_O_SUSPEND_SYSCALL_USER_DISPATCH) && > + (!IS_ENABLED(CONFIG_CHECKPOINT_RESTART))) > + return -EINVAL; Hmm? git grep CHECKPOINT_RESTART shows nothing. Oleg.