Re: [PATCH 14/19] util/async: Fixed tsan warnings

From: Robert Foley <robert.foley@linaro.org>
To: "Emilio G. Cota" <cota@braap.org>
Cc: "Fam Zheng" <fam@euphon.net>,
	"Peter Puhov" <peter.puhov@linaro.org>,
	"Alex Bennée" <alex.bennee@linaro.org>,
	"QEMU Developers" <qemu-devel@nongnu.org>,
	"Stefan Hajnoczi" <stefanha@redhat.com>
Subject: Re: [PATCH 14/19] util/async: Fixed tsan warnings
Date: Tue, 26 May 2020 11:19:35 -0400	[thread overview]
Message-ID: <CAEyhzFt5Yxt6DVDJrhfnV+WjJuuoS9=t_tETM58KbkaUashqyw@mail.gmail.com> (raw)
In-Reply-To: <20200523201246.GF382220@sff>

On Sat, 23 May 2020 at 16:12, Emilio G. Cota <cota@braap.org> wrote:
>
> On Fri, May 22, 2020 at 12:07:50 -0400, Robert Foley wrote:
<snip>
>
> >      QSIMPLEQ_INSERT_TAIL(&ctx->bh_slice_list, &slice, next);
> >
> >      while ((s = QSIMPLEQ_FIRST(&ctx->bh_slice_list))) {
> > @@ -280,14 +285,16 @@ aio_ctx_check(GSource *source)
> >      aio_notify_accept(ctx);
> >
> >      QSLIST_FOREACH_RCU(bh, &ctx->bh_list, next) {
> > -        if ((bh->flags & (BH_SCHEDULED | BH_DELETED)) == BH_SCHEDULED) {
> > +        if ((atomic_read(&bh->flags) & (BH_SCHEDULED | BH_DELETED))
> > +             == BH_SCHEDULED) {
> >              return true;
> >          }
> >      }
> >
> >      QSIMPLEQ_FOREACH(s, &ctx->bh_slice_list, next) {
> >          QSLIST_FOREACH_RCU(bh, &s->bh_list, next) {
> > -            if ((bh->flags & (BH_SCHEDULED | BH_DELETED)) == BH_SCHEDULED) {
> > +            if ((atomic_read(&bh->flags) & (BH_SCHEDULED | BH_DELETED))
> > +                 == BH_SCHEDULED) {
>
> This hunk like the real fix. Also, I'd put "fix race" in the commit
> title as opposed to "fix warning" since fixing races is the goal, not
> fixing warnings.

Good point, will update the commit.

Thanks & Regards,
-Rob
>
> Thanks,
>
>                 Emilio