Re: [PATCH v5 6/6] signal: Don't restart fork when signals come in.

[Eric W. Biederman]

Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> writes:

> On Wed, Aug 8, 2018 at 11:57 PM Eric W. Biederman <ebiederm@xxxxxxxxxxxx> wrote:
>>
>> The code was being overly pesimistic.
>
> Pessimistic.

>> +       if (type > PIDTYPE_TGID) {
>> +               struct multiprocess_signals *delayed;
>> +               hlist_for_each_entry(delayed, &t->signal->multiprocess, node) {
>> +                       sigset_t *signal = &delayed->signal;
>> +                       /* Can't queue both a stop and a continue signal */
>> +                       if (sig == SIGCONT) {
>> +                               sigset_t flush;
>> +                               siginitset(&flush, SIG_KERNEL_STOP_MASK);
>> +                               sigandnsets(signal, signal, &flush);
>
> This looks odd and unnecessary.
>
> Why isn't this just a
>
>         sigdelsetmask(signal, SIG_KERNEL_STOP_MASK);
>
> since all of the traditional stop bits should be in the low mask.
>
> I see that we apparently have this stupid pattern elsewhere too, and
> it looks like it's because we stupidly say "are the RT signals in the
> non-legacy set", when that definitely cannot be the case for the (very
> much legacy) tty flow control signals.

I just missed the existence of sigdelsetmask when I was putting this
together.

I will fix that and unless someone sees an issue I will queue this up
for linux-next.

Eric