CVE-2026-53171

In the Linux kernel, the following vulnerability has been resolved:

accel/ethosu: fix arithmetic issues in dma_length()

dmalength() derives DMA region usage from command stream values and updates regionsize[]:

len = ((len + stride[0]) * size0 + stride[1]) * size1
region_size[region] = max(..., len + dma->offset)

Several arithmetic issues can corrupt the derived region size:

• signed stride values may underflow when added to len
• intermediate multiplications may overflow
• len + dma->offset may overflow during region_size updates
• dma_length() error returns were not validated by the caller

regionsize[] is later used by ethosujob.c to validate command stream accesses against GEM buffer sizes. Arithmetic wraparound can therefore under-report region usage and bypass the bounds validation.

Fix by validating signed additions, using overflow helpers for multiplications and offset updates, and propagating dma_length() failures to the caller.