CVE-2025-71079

In the Linux kernel, the following vulnerability has been resolved: net: nfc: fix deadlock between nfc_unregister_device and rfkill_fop_write A deadlock can occur between nfc_unregister_device() and rfkill_fop_write() due to lock ordering inversion between device_lock and rfkill_global_mutex. The problematic lock order is: Thread A (rfkill_fop_write): rfkill_fop_write() mutex_lock(&rfkill_global_mutex) rfkill_set_block() nfc_rfkill_set_block() nfc_dev_down() device_lock(&dev->dev) <- waits for device_lock Thread B (nfc_unregister_device): nfc_unregister_device() device_lock(&dev->dev) rfkill_unregister() mutex_lock(&rfkill_global_mutex) <- waits for rfkill_global_mutex This creates a classic ABBA deadlock scenario. Fix this by moving rfkill_unregister() and rfkill_destroy() outside the device_lock critical section. Store the rfkill pointer in a local variable before releasing the lock, then call rfkill_unregister() after releasing device_lock. This change is safe because rfkill_fop_write() holds rfkill_global_mutex while calling the rfkill callbacks, and rfkill_unregister() also acquires rfkill_global_mutex before cleanup. Therefore, rfkill_unregister() will wait for any ongoing callback to complete before proceeding, and device_del() is only called after rfkill_unregister() returns, preventing any use-after-free. The similar lock ordering in nfc_register_device() (device_lock -> rfkill_global_mutex via rfkill_register) is safe because during registration the device is not yet in rfkill_list, so no concurrent rfkill operations can occur on this device.

• linux linux kernel (>= 4.4.293 < 4.5) • linux linux kernel (>= 4.9.291 < 4.10) • linux linux kernel (>= 4.14.256 < 4.15) • linux linux kernel (>= 4.19.218 < 4.20) • linux linux kernel (>= 5.4.162 < 5.5) • linux linux kernel (>= 5.10.82 < 5.10.248) • linux linux kernel (>= 5.15.5 < 5.15.198) • linux linux kernel (>= 5.16.1 < 6.1.160) • linux linux kernel (>= 6.2 < 6.6.120) • linux linux kernel (>= 6.7 < 6.12.64) • linux linux kernel (>= 6.13 < 6.18.4) • linux linux kernel 5.16 • linux linux kernel 6.19