iommufd: Don't overflow during division for dirty tracking

Browse source

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.

Link: https://patch.msgid.link/r/0-v1-663679b57226+172-iommufd_dirty_div0_jgg@nvidia.com
Cc: stable@vger.kernel.org
Fixes: 58ccf0190d ("vfio: Add an IOVA bitmap support")
Reviewed-by: Joao Martins <joao.m.martins@oracle.com>
Reviewed-by: Nicolin Chen <nicolinc@nvidia.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reported-by: syzbot+093a8a8b859472e6c257@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=093a8a8b859472e6c257
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

...

This commit is contained in:

Jason Gunthorpe 2025-10-08 15:17:18 -03:00

parent 211ddde082

commit cb30dfa75d

1 changed files with 2 additions and 3 deletions

Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL

Download patch file Download diff file Expand all files Collapse all files

5

drivers/iommu/iommufd/iova_bitmap.c

View file