CVE-2026-64472

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

vfio/mlx5: Fix racy bitfields and tighten struct layout

Bitfield operations are not atomic, they use a read-modify-write pattern, therefore we should be careful not to pack bitfields that can be concurrently updated into the same storage unit.

This split takes a binary approach: flags that are only modified pre/post open/close remain bitfields, flags modified from user action, including actions that reach across to another device (ex. reset) use dedicated storage units.

Note mlx5vhcapage_tracker.status is relocated to fill the alignment hole this split exposes.

Bitfield justifications:

migratecap: written only in mlx5vfcmdsetmigratable() at probe chunkmode: written only in mlx5vfcmdsetmigratable() at probe migstatecap: written only in mlx5vfcmdset_migratable() at probe

Dedicated storage units:

mdevdetach: written in the VF attach/detach event notifier mlx5fvvfevent() at runtime logactive: written in mlx5vfstartpagetracker()/ mlx5vfstoppagetracker() during runtime dirty tracking deferredreset: written in mlx5vfstatemutexunlock()/ mlx5vfpciaerresetdone() during runtime reset handling iserr: set by tracker error handling and dirty-log polling at runtime objectchanged: set by tracker event handling and cleared by dirty-log polling at runtime