Re: [PATCH] eventfd signal race in aio_complete()

[Jeff Roberson]

On Sat, 8 Mar 2008, Davide Libenzi wrote:

> On Sat, 8 Mar 2008, Rik van Riel wrote:
>
> > On Fri, 7 Mar 2008 20:29:20 -0800 (PST)
> > Davide Libenzi <davidel@xxxxxxxxxxxxxxx> wrote:
> >
> > > The second solution/patch simply moves the eventfd_signal() call before
> > > the __aio_put_req() call, but after the event has beed "ringed".
> > > We should be clear to go with the shorter/nicer second solution. Those
> > > patches builds, but I'm not even signing them off till I tested them.
> >
> > If there are no spinlock ordering issues between &ctx->ctx_lock
> > and &ctx->wqh.lock (taken inside eventfd_signal), then the second
> > patch is indeed preferable.
> >
> > Jeff and I did look at that briefly last night, but were not
> > familiar enough with the code to decide whether or not that was
> > safe.
>
> There's no interlocking between the two, so let's go with #2.
> Jeff, would you mind giving patch #2 a spin in your test suite?

I agree #2 would be best as well.  It may take me a few days due to some 
equipment issues but I will get back to you as soon as I can.

Thanks,
Jeff

> - Davide
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