Medium [CVE-2026-74622] free RX pages of consumed but not refilled buffers

In the Linux kernel, the following vulnerability has been resolved: net: atlantic: free RX pages of consumed but not refilled buffers aq_ring_rx_deinit() only walks [sw_head, sw_tail), the region posted to hardware.

Since the page reuse strategy was added, a cleaned RX buffer keeps its page (and its DMA mapping) in the ring for reuse, and refill is batched: aq_ring_rx_fill() returns early until AQ_CFG_RX_REFILL_THRES slots are free.

Slots that were consumed but not yet reposted therefore sit in the complementary [sw_tail, sw_head) gap with a live page, and the deinit walk never visits them: up to a refill batch worth of pages and DMA mappings leak on every interface down. Walk the whole ring instead and release whatever is still there.

Also bail out if the buffer ring is already gone: a partial aq_ptp_ring_alloc() failure frees the ring but leaves aq_nic set, so aq_ptp_ring_deinit() still gets here on the unwind path. A flaw was found in the Linux kernel's 'atlantic' network driver.

The `aq_ring_rx_deinit()` function, responsible for deinitializing receive (RX) buffers, fails to properly free pages and their associated Direct Memory Access (DMA) mappings for buffers that have been consumed but not yet refilled. This oversight leads to a memory leak each time a network interface utilizing this driver is brought down.