Re: [PATCH] x86_64: fix delayed signals

Andi Kleen
2008-07-13T18:59:25Z

Linus Torvalds wrote:
>
> On Sun, 13 Jul 2008, Andi Kleen wrote:
>> At least the original report was about Ctrl-C only versus Ctrl-Z.
>
> Yes, and I explained why.
>
>> I see the problem regularly myself that Ctrl-C doesn't work,
>> but Ctrl-Z+kill does (although I unfortunately cannot
>> reproduce it on demand).
>
> There's no way you _can_ reproduce it.

That's not how I remember it from seeing it here, but ok it's possible my
memory is fuzzy and I'm misremembering. I'll continue to watch it.

While the bit about color ls (which I use here) catching signals was
also interesting I wouldn't expect the color ls to take longer to
process Ctrl-C even if it hits user space because it shouldn't
do anything block here (unless the terminal is in flow control,
but is unlikely)

> Two facts:
>
> - ^Z and ^C are both going to be equally fast if they aren't blocked.
>
> This is just how things are. They are handled by the same codepaths.

Yes I know that, that is why the behavior always puzzled me, because
it apparently contradicts that. I think I know reasonably well how
signals work, but cannot say the same about tty, so my guess was
in that area. But we'll see.

-Andi