CVE-2026-74354

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

bpf: Take mmap_lock in zap_pages()

zap_vma_range() requires the owning mm's mmap_lock to be held.

Taking mmap_read_lock under arena->lock would AB-BA against

arena_vm_close() and arena_map_mmap(), both of which run with

mmap_write_lock held and then acquire arena->lock. Instead drop

arena->lock, mmget_not_zero() the vma's mm, take mmap_read_lock, and

re-resolve the vma via find_vma() since it may have been unmapped or

replaced while waiting.

Track processed vmls with a per-call generation in vml->zap_gen and

serialize zap_pages() callers with a new arena->zap_mutex so

concurrent callers on different uaddr ranges do not mark each other's

vmls processed before the zap is done.