On Tue, Nov 25, 2025 at 05:11:18PM -0800, Alex Mastro wrote:
> fill_sg_entry() splits large DMA buffers into multiple scatter-gather
> entries, each holding up to UINT_MAX bytes. When calculating the DMA
> address for entries beyond the second one, the expression (i * UINT_MAX)
> causes integer overflow due to 32-bit arithmetic.
>
> This manifests when the input arg length >= 8 GiB results in looping for
> i >= 2.
>
> Fix by casting i to dma_addr_t before multiplication.
>
> Fixes: 3aa31a8bb11e ("dma-buf: provide phys_vec to scatter-gather mapping
> routine")
> Signed-off-by: Alex Mastro <[email protected]>
> ---
> More color about how I discovered this in [1] for the commit at [2]:
>
> [1] https://lore.kernel.org/all/[email protected]
> [2]
> https://lore.kernel.org/all/[email protected]
> ---
> drivers/dma-buf/dma-buf-mapping.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
Reviewed-by: Jason Gunthorpe <[email protected]>
AlexW, can you pick this up?
Thanks,
Jason
