In the Linux kernel, the following vulnerability has been resolved: nfc: pn533: hold a reference to the request skb during send_frame __pn533_send_async() publishes the command and then calls dev->phy_ops->send_frame(). Once dev->cmd is set, an incoming frame can be matched to this command: the I2C threaded IRQ runs pn533_recv_frame(), which queues cmd_complete_work, and pn533_send_async_complete() frees cmd->req with consume_skb(). On the I2C transport, pn533_i2c_send_frame() still dereferences the same skb after i2c_master_send() returns, so a completion that races the send can free the skb while the transport is still using it. The request skb is owned by the command object and may be freed by command completion at any time after dev->cmd is published, so the transport send path must not assume it stays alive. Hold a temporary reference to the request skb across the send_frame() call so the transport always sees a live skb even if completion races the send. Add a pn533_send_cmd_frame() helper and use it from all three send paths.
https://git.kernel.org/stable/c/d329f61ad5786900334a54c2445dc99feda545bf
https://git.kernel.org/stable/c/8710faddef4ad8b2a6bfa985d896e2e1bfb77018
https://git.kernel.org/stable/c/7ee72c64b4b66b1b42dbddbca0a80a218f1b9297
https://git.kernel.org/stable/c/7a8e0a7aef80721da287ac246349aba7d98f6aed
https://git.kernel.org/stable/c/753bdaf3220fe8371a6c3c75da645ea7753d11be
https://git.kernel.org/stable/c/47792358a624ea066455ef86b744159928cd7716
https://git.kernel.org/stable/c/3e7a093c177f9f8b9fd039cab41191515079425a
https://git.kernel.org/stable/c/19f1239758c23f087f4c25733cfcf62bf0b06051