From: Alex Williamson <alex.williamson@redhat.com>
To: Peter Xu <peterx@redhat.com>
Cc: iommu@lists.linux-foundation.org, tursulin@ursulin.net,
dwmw2@infradead.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] iommu/vt-d: Fix shift overflow in qi_flush_dev_iotlb
Date: Wed, 13 Dec 2017 08:58:47 -0700 [thread overview]
Message-ID: <20171213085847.3d3245c6@t450s.home> (raw)
In-Reply-To: <20171213071355.GD7780@xz-mi>
On Wed, 13 Dec 2017 15:13:55 +0800
Peter Xu <peterx@redhat.com> wrote:
> On Tue, Dec 12, 2017 at 03:43:08PM -0700, Alex Williamson wrote:
>
> [...]
>
> > diff --git a/drivers/iommu/dmar.c b/drivers/iommu/dmar.c
> > index 9a7ffd13c7f0..87888b102057 100644
> > --- a/drivers/iommu/dmar.c
> > +++ b/drivers/iommu/dmar.c
> > @@ -1345,7 +1345,9 @@ void qi_flush_dev_iotlb(struct intel_iommu *iommu, u16 sid, u16 qdep,
> > struct qi_desc desc;
> >
> > if (mask) {
> > - BUG_ON(addr & ((1 << (VTD_PAGE_SHIFT + mask)) - 1));
> > + BUG_ON((mask > MAX_AGAW_PFN_WIDTH) ||
> > + ((mask == MAX_AGAW_PFN_WIDTH) && addr) ||
> > + (addr & ((1 << (VTD_PAGE_SHIFT + mask)) - 1)));
>
> Could it work if we just use 1ULL instead of 1 here? Thanks,
In either case we're talking about shifting off the end of the
variable, which I understand to be undefined. Right? Thanks,
Alex
next prev parent reply other threads:[~2017-12-13 15:58 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-12-12 22:43 Alex Williamson
2017-12-13 7:13 ` Peter Xu
2017-12-13 15:58 ` Alex Williamson [this message]
2017-12-13 16:41 ` Hook, Gary
2017-12-13 17:15 ` Alex Williamson
2017-12-13 17:31 ` Hook, Gary
2017-12-15 7:29 ` Peter Xu
2017-12-15 3:12 ` kbuild test robot
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