Re: Re: Strange Linux behaviour with blocking syscalls and stop signals+SIGCONT

[Linus Torvalds <torvalds@osdl.org>]

On Fri, 7 Jul 2006, Michael Kerrisk wrote:
> Von: Linus Torvalds <torvalds@osdl.org>
> > On Thu, 6 Jul 2006, Manfred Spraul wrote:
> > > 
> > > Is it necessary that the futex syscall ignores SA_RESTART?
> > 
> > Very possibly. That was definitely the case for "select()" long ago.
> 
> Why was this necesary back then?

I forget the exact details, but certain X applications would stop 
responding, because they would restart their select() system call in their 
main select-loop, rather than go through the loop.

I _think_ it was SIGALARM installed with SA_RESTART (and doing itimers 
every 10 ms), but I didn't really care enough - we had select() return 
ERESTARTSYS for exactly one day back in 199x, and when I figured out what 
broke, it got reverted pronto.

I want to say that the failing app was "oneko" (damn, I should try to find 
if it still exists - brings back memories of an earlier time), but the 
point being that it's enough that one app breaks.

			Linus
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