CVE-2026-72169

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

kho: make sure scratch size is always aligned by CMA_MIN_ALIGNMENT_BYTES

When using scratch_scale, the scratch sizes are rounded up to
CMA_MIN_ALIGNMENT_BYTES since they will be released as MIGRATE_CMA. This
is not done when using fixed scratch sizes via command line. This can
result in user specifying a size which is not aligned, and thus kernel
releasing a pageblock that is only partially scratch.

Do the rounding up for both cases in scratch_size_update().