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a=6eWqkTHjU83fiwn7nKZWdM+Sl24=:19 a=z/mQ4Ysz8XfWz/Q5cLBRGdckG28=:19 a=lCpzRmAYbLLaTzLvsPZ7Mbvzbb8=:19 a=xqWC_Br6kY4A:10 a=IkcTkHD0fZMA:10 a=x6icFKpwvdMA:10 a=GoEa3M9JfhUA:10 a=edf1wS77AAAA:8 a=VwQbUJbxAAAA:8 a=hSkVLCK3AAAA:8 a=Ikd4Dj_1AAAA:8 a=yPCof4ZbAAAA:8 a=Pyf4ynxWdgcanfih80kA:9 a=QEXdDO2ut3YA:10 a=DcSpbTIhAlouE1Uv7lRv:22 a=cQPPKAXgyycSBL8etih5:22 cc=ntf awl=host:13624 X-Proofpoint-GUID: 7ztu87sNOCOLgRHhrYTGvfkxFIN4I1kM X-Proofpoint-Spam-Details-Enc: AW1haW4tMjUxMDA4MDEyMSBTYWx0ZWRfXyQLQgWHszE3T CHXXobRT1Y4rkZTtC/iQTZWhaQlVodcmpdc5SX9PYdS4ke5a1Y2E1uvoBjiMKnZ3upkAukYapip 117hHuVhHe4xBYsVjLMIgkWOa0wwa+2SA3GwpDzU7kYtgXnHyjloQ/P0klyZzLEJzYc4ScZKapa x6KcKJljTcIMotf1pjvD5d+xYzzBvzvoDtR0aHMevVUOiBt9U6PnnKoXCRxN8/WfnQOWJsm+H89 Jnjkuu/XflsYMf283ttvG9KuqV8smRlC3FIS6cMW/aXr/gMIiVY7/rfZ+j7jIpyW0YWFGWxyEzu sXYAhL7DCtd97r1fg7PeMQ+is+LEVHdRGzfR5FZMqFhUiXk5eDeBhZ9sB7KkVG8MELH/j+sfTAs kgmO6xciGciJ+S7ir7nB9wznJONib1WduQYIyJ1n3qhznaAJw5s= On 08/10/2025 19:17, 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 Reviewed-by: Joao Martins > --- > drivers/iommu/iommufd/iova_bitmap.c | 5 ++--- > 1 file changed, 2 insertions(+), 3 deletions(-) > > diff --git a/drivers/iommu/iommufd/iova_bitmap.c b/drivers/iommu/iommufd/iova_bitmap.c > index 4514575818fc07..b5b67a9d3fb35e 100644 > --- a/drivers/iommu/iommufd/iova_bitmap.c > +++ b/drivers/iommu/iommufd/iova_bitmap.c > @@ -130,9 +130,8 @@ struct iova_bitmap { > static unsigned long iova_bitmap_offset_to_index(struct iova_bitmap *bitmap, > unsigned long iova) > { > - unsigned long pgsize = 1UL << bitmap->mapped.pgshift; > - > - return iova / (BITS_PER_TYPE(*bitmap->bitmap) * pgsize); > + return (iova >> bitmap->mapped.pgshift) / > + BITS_PER_TYPE(*bitmap->bitmap); > } > > /* > > base-commit: 2a918911ed3d0841923525ed0fe707762ee78844