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From: David Marchand <david.marchand@redhat.com>
To: "Burakov, Anatoly" <anatoly.burakov@intel.com>,
	Michael Haeuptle <michael.haeuptle@hpe.com>
Cc: dev <dev@dpdk.org>
Subject: Re: [dpdk-dev] [PATCH] eal: Fixes VFIO/sysfs race condition
Date: Mon, 6 Apr 2020 15:25:05 +0200	[thread overview]
Message-ID: <CAJFAV8ztA6D7=aUhTe=JxHJRpgxp89C+3Pr00UFnAP-GWFBfyg@mail.gmail.com> (raw)
In-Reply-To: <a892528d-33d1-b5ff-93ca-dd1e5afa84f0@intel.com>

On Thu, Apr 2, 2020 at 12:11 PM Burakov, Anatoly
<anatoly.burakov@intel.com> wrote:
>
> On 31-Mar-20 5:56 PM, Michael Haeuptle wrote:
> > This fix treats a 0 return value from vfio_open_group_fd
> > in vfio_get_group_fd as the intended error condition instead
> > of putting an incorrect 0 file descriptor in the vfio_group table.
> >
> > Sometimes, the creation of device files in sysfs is not
> > instantaneously causing vfio_open_groupfd to return 0.
> > This has been observed when hot removing/adding multiple
> > NVMe devices (>=4).
> >
> > Signed-off-by: Michael Haeuptle <michael.haeuptle@hpe.com>
> > ---
> >   lib/librte_eal/linux/eal_vfio.c | 2 +-
> >   1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/lib/librte_eal/linux/eal_vfio.c b/lib/librte_eal/linux/eal_vfio.c
> > index 4502aefed..1979f6fdd 100644
> > --- a/lib/librte_eal/linux/eal_vfio.c
> > +++ b/lib/librte_eal/linux/eal_vfio.c
> > @@ -379,7 +379,7 @@ vfio_get_group_fd(struct vfio_config *vfio_cfg,
> >       }
> >
> >       vfio_group_fd = vfio_open_group_fd(iommu_group_num);
> > -     if (vfio_group_fd < 0) {
> > +     if (vfio_group_fd <= 0) {
> >               RTE_LOG(ERR, EAL, "Failed to open group %d\n", iommu_group_num);
> >               return -1;
> >       }
> >
>
> If it's returning an invalid value, is that a kernel bug?
>
> I mean, looks fine to me, so
>
> Acked-by: Anatoly Burakov <anatoly.burakov@intel.com>

We are missing a fixes line.
Does this deserve a backport?


-- 
David Marchand


  reply	other threads:[~2020-04-06 13:25 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-31 16:56 Michael Haeuptle
2020-04-01  8:50 ` Stojaczyk, Dariusz
2020-04-02 10:10 ` Burakov, Anatoly
2020-04-06 13:25   ` David Marchand [this message]
2020-04-06 19:15     ` Haeuptle, Michael
2020-04-06 20:08       ` David Marchand
  -- strict thread matches above, loose matches on Subject: below --
2020-04-06 22:23 Michael Haeuptle
2020-04-21 16:19 ` David Marchand
2020-04-06 22:16 Michael Haeuptle
2020-03-31 16:51 Michael Haeuptle

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