CyberRota Analysis
AI-GeneratedThe vulnerability affects the iwlwifi driver in the Linux kernel, where a failure in the firmware during high-throughput conditions can lead to excessive CPU usage and memory pressure due to a failure loop in the transmission process. Specifically, when the firmware crashes, the driver continues to dequeue frames without checking the firmware status, resulting in rapid allocation and deallocation of memory. Organizations using affected Linux systems, particularly those relying on Intel Wi-Fi 7 hardware and high-throughput applications, should prioritize applying the patch to mitigate performance degradation and potential system instability.
Original NVD Description
In the Linux kernel, the following vulnerability has been resolved: wifi: iwlwifi: mld: stop TX during firmware restart When iwlwifi firmware crashes (e.g., NMI_INTERRUPT_UNKNOWN on Intel BE201/Wi-Fi 7), iwl_mld_nic_error() sets mld->fw_status.in_hw_restart to true. However, iwl_mld_tx_from_txq() does not check this flag before dequeuing frames from mac80211 and pushing them to the transport layer. Since the firmware is dead, iwl_trans_tx() returns -EIO for each frame, which then gets freed immediately. Under high-throughput conditions (e.g., Tailscale UDP traffic or active SSH sessions), this creates a tight dequeue-send-fail-free loop that wastes CPU cycles and generates rapid skb allocation churn, leading to memory pressure from slab fragmentation. The RX path already has this guard (iwl_mld_rx_mpdu checks in_hw_restart at rx.c:1906), and so does the TXQ allocation worker (iwl_mld_add_txqs_wk at tx.c:156). Add the same guard to iwl_mld_tx_from_txq() to stop all TX during firmware restart. Frames left in mac80211's TXQs are naturally drained after restart completes, when queue reallocation triggers iwl_mld_tx_from_txq() via iwl_mld_add_txq_list(), or when new upper-layer traffic invokes wake_tx_queue. Tested on ASUS Zenbook 14 UX3405CA with Intel BE201 (Wi-Fi 7) on kernel 6.19.5 where the firmware crashes approximately every 10-15 minutes under Tailscale traffic.
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