On 09/22, Waiman Long wrote: > > This patch is currently only active for 64-bit architectures.
Why? > --- a/kernel/signal.c > +++ b/kernel/signal.c > @@ -2485,6 +2485,16 @@ void __set_current_blocked(const sigset_t *newset) > { > struct task_struct *tsk = current; > > + /* > + * In case the signal mask hasn't changed, we won't need to take > + * the lock. As the current blocked mask can be modified by other > + * CPUs, No, nobody else should modify current->blocked. Yes, we need to cleanup the usage of force_sig_info(), and probably remove the "struct task_struct *t" argument. > we need to do an atomic read without lock. In other words, > + * this check will only be done on 64-bit systems. > + */ > +#if _NSIG_WORDS == 1 > + if (READ_ONCE(tsk->blocked.sig[0]) == newset->sig[0]) > + return; > +#endif OK, agreed, but this should not depend on _NSIG_WORDS == 1 and READ_ONCE() looks confusing. It seems you need to add the new helper into include/linux/signal.h. Oleg.