On Fri, Dec 11, 2015 at 03:30:33AM -0800, Paul Turner wrote:
> > Blergh, all I've managed to far is to confuse myself further. Even
> > something like the original (+- the EINTR) should work when we consider
> > the looping, even when mixed with an occasional spurious wakeup.
> >
> >
> > int bit_wait()
> > {
> > if (signal_pending_state(current->state, current))
> > return -EINTR;
> > schedule();
> > }
So I asked Vladimir to test that (simply changing the return from 1 to
-EINTR) and it made his fail much less likely but it still failed in the
same way.
So I'm fairly sure I'm still missing something :/
> Hugh asked me about this after seeing a crash, here's another exciting
> way in which the current code breaks -- this one actually quite
> serious:
Yep, this got reported by Jan and I did kick myself for that.
> Peter's proposed follow-up above looks strictly more correct. We need
> to evaluate the potential existence of a signal, *after* we return
> from schedule, but in the context of the state which we previously
> _entered_ schedule() on.
>
> Reviewed-by: Paul Turner <[email protected]>
Right, its maybe a bit overkill, but at this point I'm a tad
conservative/paranoid.
Vladimir, Jan could you both please that patch?
lkml.kernel.org/r/[email protected]
Thanks!
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