From: Jason Gunthorpe <jgg@nvidia.com>
To: iommu@lists.linux.dev, Joerg Roedel <joro@8bytes.org>,
Kevin Tian <kevin.tian@intel.com>,
Robin Murphy <robin.murphy@arm.com>,
Will Deacon <will@kernel.org>
Cc: Alex Williamson <alex.williamson@redhat.com>,
Joao Martins <joao.m.martins@oracle.com>,
patches@lists.linux.dev, stable@vger.kernel.org,
syzbot+093a8a8b859472e6c257@syzkaller.appspotmail.com,
Yishai Hadas <yishaih@nvidia.com>
Subject: Re: [PATCH rc] iommufd: Don't overflow during division for dirty tracking
Date: Mon, 20 Oct 2025 19:59:47 -0300 [thread overview]
Message-ID: <20251020225947.GA644827@nvidia.com> (raw)
In-Reply-To: <0-v1-663679b57226+172-iommufd_dirty_div0_jgg@nvidia.com>
On Wed, Oct 08, 2025 at 03:17:18PM -0300, Jason Gunthorpe wrote:
> If pgshift is 63 then BITS_PER_TYPE(*bitmap->bitmap) * pgsize will overflow
> to 0 and this triggers divide by 0.
>
> In this case the index should just be 0, so reorganize things to divide
> by shift and avoid hitting any overflows.
>
> Cc: stable@vger.kernel.org
> Fixes: 58ccf0190d19 ("vfio: Add an IOVA bitmap support")
> Reported-by: syzbot+093a8a8b859472e6c257@syzkaller.appspotmail.com
> Closes: https://syzkaller.appspot.com/bug?extid=093a8a8b859472e6c257
> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
> ---
> drivers/iommu/iommufd/iova_bitmap.c | 5 ++---
> 1 file changed, 2 insertions(+), 3 deletions(-)
Applied to for-rc
Thanks,
Jason
prev parent reply other threads:[~2025-10-20 22:59 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-10-08 18:17 [PATCH rc] iommufd: Don't overflow during division for dirty tracking Jason Gunthorpe
2025-10-08 18:57 ` Nicolin Chen
2025-10-08 21:35 ` Joao Martins
2025-10-16 7:36 ` Tian, Kevin
2025-10-20 22:59 ` Jason Gunthorpe [this message]
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