dma-buf: Fix silent overflow for phys vec to sgt

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In case MMIO size is bigger than 4G and peer2peer DMA goes
through host bridge, we trigger a code path that assigns the
total linked IOVA (which is greater than 4G) to mapped_len.

Previously, `mapped_len` was declared as 32-bit `unsigned int`.
When accumulating `size_t` lengths, this leads to a silent wrap-around.
This truncation causes truncated lengths to be passed to functions
like `fill_sg_entry()`.

Fix this by changing `mapped_len` to `size_t` (64-bit). While
at it, fix similar potential overflow issues in `calc_sg_nents`
by using `check_add_overflow()` for `nents` and using
`unsigned int` for the loop iterator in `fill_sg_entry` to match.

Fixes: 3aa31a8bb1 ("dma-buf: provide phys_vec to scatter-gather mapping routine")
Cc: stable@vger.kernel.org
Cc: iommu@lists.linux.dev
Reviewed-by: Pranjal Shrivastava <praan@google.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: David Hu <xuehaohu@google.com>
Signed-off-by: Christian König <christian.koenig@amd.com>
Link: https://lore.kernel.org/r/20260901170849.4052816-2-dhu@x6u.co

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David Hu 2026-09-01 17:08:48 +00:00 • committed by Christian König

parent 143755bdab

commit b344ca94e8

1 changed files with 12 additions and 4 deletions

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drivers/dma-buf/dma-buf-mapping.c

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