CyberRota Analysis
AI-GeneratedThe vulnerability in the Linux kernel's firmware loader affects the power management notification handler, where a recursive locking deadlock can occur during system suspend or hibernation. This issue arises when the firmware cache state is updated while holding a lock, leading to potential system hangs if memory allocation fails during asynchronous work scheduling. Linux system administrators and developers should prioritize this fix to prevent system instability during critical power management operations.
Original NVD Description
In the Linux kernel, the following vulnerability has been resolved: firmware_loader: Fix recursive lock in device_cache_fw_images() A recursive locking deadlock can occur in the firmware loader's power management notification handler. During system suspend or hibernation preparation, fw_pm_notify() calls device_cache_fw_images(). This function acquires fw_lock to set the firmware cache state to FW_LOADER_START_CACHE and then iterates over all devices using dpm_for_each_dev() while still holding the lock. For each device, dev_cache_fw_image() schedules asynchronous work to cache the firmware. If memory allocation for the async work entry fails (e.g., in out-of-memory conditions), async_schedule_node_domain() falls back to executing the work function synchronously in the current thread. The synchronous execution path (__async_dev_cache_fw_image() -> cache_firmware() -> request_firmware() -> assign_fw()) attempts to acquire fw_lock again. Since the current thread already holds fw_lock, this results in a recursive locking deadlock. Fix this by releasing fw_lock immediately after updating the cache state and before calling dpm_for_each_dev(). The lock is only needed to protect the state update. Concurrent firmware requests will correctly see the FW_LOADER_START_CACHE state and use the piggyback mechanism, which is independently protected by its own fwc->name_lock.