In the Linux kernel, the following vulnerability has been resolved:
net: page_pool: fix use-after-free in page_pool_recycle_ring_bulk()
With CONFIG_PAGE_POOL_STATS=y, page_pool_recycle_ring_bulk() updates
the recycle stats after dropping the producer lock. If it just recycled
the last inflight netmems of a pool being destroyed, page_pool_release()
can pass its producer-lock barrier and free the pool before
recycle_stat_add() runs.
Commit fcc680a647ba7 (“page_pool: allow mixing PPs within one bulk”)
moved this stat update after the unlock. Commit 271683bb2cf32
(“page_pool: Fix use-after-free in page_pool_recycle_in_ring”) later
added the barrier, but only fixed page_pool_recycle_in_ring(). Move
the update back under the lock.
