Re: [rfc][patch] futex: restartable futex_wait?

From: Nick Piggin
Date: Fri Mar 09 2007 - 00:11:10 EST


On Thu, Mar 08, 2007 at 06:29:02PM +0100, Ingo Molnar wrote:
>
> * Nick Piggin <npiggin@xxxxxxx> wrote:
>
> > Hi Ingo,
> >
> > I'm seeing an LTP test fail for ltp test sigaction_16_24. Basically,
> > it tests whether the SA_RESTART flag works for the sem_wait operation.
> >
> > I see sem_wait is implemented with futex_wait, so I wonder whether we
> > can make it restartable? Am I going about it the right way? (Seems to
> > fix the testcase here).
>
> i think that's quite right. I'm wondering why this never came up before?
> But your fix is not complete i think:
>
> > + restart->arg2 = time;
> > + return -ERESTART_RESTARTBLOCK;
> > + }
>
> 'time' here is relative, so the restarted syscall will do a /full/ wait
> again.

But it has been modified by schedule_timeout?

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