On Mon, 3 Mar 2025 10:51:30 +0100
Corinna Vinschen wrote:
> On Mar 1 08:33, Takashi Yano wrote:
> > The PID_STOPPED flag in _ponfo::process_state is sometimes accidentally
> > cleared due to a race condition when modifying it with the "|=" or "&="
> > operators. This patch uses InterlockedOr/And() instead to avoid the
> > race condition.
>
> Is this really sufficent? I'm asking because of...
>
> > @@ -678,8 +678,9 @@ dofork (void **proc, bool *with_forkables)
> >
> > if (ischild)
> > {
> > - myself->process_state |= PID_ACTIVE;
> > - myself->process_state &= ~(PID_INITIALIZING | PID_EXITED |
> > PID_REAPED);
> > + InterlockedOr ((LONG *) &myself->process_state, PID_ACTIVE);
> > + InterlockedAnd ((LONG *) &myself->process_state,
> > + ~(PID_INITIALIZING | PID_EXITED | PID_REAPED));
> > }
> > else if (res < 0)
> > {
>
> ...places like these. Every single Interlocked call is safe in itself,
> but what if somebody else changes something between the two interlocked
> calls? Maybe this should be done with InterlockedCompareExchange.
Thanks for reviewing.
How can we guard that situation by using InterlockedCompareExchange()?
Could you please give me some more instruction?
--
Takashi Yano <takashi.y...@nifty.ne.jp>
