swiotlb: use the adjusted address for the highmem page lookup

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swiotlb_bounce() reads the page frame number from the slot's recorded
orig_addr, then advances orig_addr by tlb_offset to reach the address
the caller asked about. The highmem branch mixes the two: the offset
within the page comes from the adjusted address, the page from the value
before it.

Once the adjustment crosses a page boundary the pair no longer describes
one location, and the whole copy lands one page below the intended one
for a positive tlb_offset, one above for a negative one. DMA_FROM_DEVICE
writes the device data over the wrong page and leaves the intended one
stale, DMA_TO_DEVICE feeds the device from a page the mapping may not
cover. Partial syncs through dma_sync_single_range_for_*() are what make
tlb_offset non-zero.

The branch test is picked the same way, so a slot recorded in lowmem can
be adjusted into highmem and the lowmem path then hands a highmem
address to phys_to_virt().

Take both from orig_addr once it is final and keep pfn in the branch
that uses it. PhysHighMem() asks the question straight from the address,
as dma-debug already does.

Fixes: 5f89468e2f ("swiotlb: manipulate orig_addr when tlb_addr has offset")
Cc: stable@vger.kernel.org
Signed-off-by: Donggeun Yoo <donggeunyoo.kernel@gmail.com>
Reviewed-by: Michael Kelley <mhklinux@outlook.com>
Link: https://lore.kernel.org/r/20260905084210.148255-1-donggeunyoo.kernel@gmail.com
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>

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This commit is contained in:

Donggeun Yoo 2026-09-05 17:42:10 +09:00 • committed by Marek Szyprowski

parent 504981db4f

commit b7d7914a9a

1 changed files with 2 additions and 2 deletions

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kernel/dma/swiotlb.c

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