net: stmmac: clear stale buf->page after recycling on skb build failure

Overview

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

net: stmmac: clear stale buf->page after recycling on skb build failure

In stmmac_rx(), when napi_build_skb() fails the descriptor page is recycled back to the page pool with page_pool_recycle_direct(), but buf->page is left pointing at the recycled page, unlike every other consumption site in the function which clears the pointer after handing the page away.

With the stale pointer stmmac_rx_refill() skips the replacement allocation and programs the already-recycled page back into the RX descriptor.

Clear buf->page on the napi_build_skb() failure path to keep the buffer lifecycle consistent with the other consumption sites.

Affected

• Linux >= df542f669307918f054a17878ff6dd1ddbb2fe18 < 501baaeca7d128fa0a2f6953cf5873c5b0d7cf89
• Linux >= df542f669307918f054a17878ff6dd1ddbb2fe18 < 298673397ea3f6f5811b84f0d9f71eac71dda2e3
• Linux >= df542f669307918f054a17878ff6dd1ddbb2fe18 < 0a7822e34a0bfde31b194ac3da3253e5032b44cc
• Linux 6.14

Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.