CVE-2025-21827

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

Bluetooth: btusb: mediatek: Add locks for usb_driver_claim_interface()

The documentation for usb_driver_claim_interface() says that the device lock is needed when the function is called from places other than probe(). This appears to be the lock for the USB interface device. The Mediatek btusb code gets called via this path:

Workqueue: hci0 hci_power_on [bluetooth] Call trace: usb_driver_claim_interface btusb_mtk_claim_iso_intf btusb_mtk_setup hci_dev_open_sync hci_power_on process_scheduled_works worker_thread kthread

With the above call trace the device lock hasnt been claimed. Claim it.

Without this fix, wed sometimes see the error Failed to claim iso interface. Sometimes wed even see worse errors, like a NULL pointer dereference (where intf->dev.driver was NULL) with a trace like:

Call trace: usb_suspend_both usb_runtime_suspend __rpm_callback rpm_suspend pm_runtime_work process_scheduled_works

Both errors appear to be fixed with the proper locking.

Weakness

The product does not properly acquire or release a lock on a resource, leading to unexpected resource state changes and behaviors.

Affected Software

Extended Description

Locking is a type of synchronization behavior that ensures that multiple independently-operating processes or threads do not interfere with each other when accessing the same resource. All processes/threads are expected to follow the same steps for locking. If these steps are not followed precisely - or if no locking is done at all - then another process/thread could modify the shared resource in a way that is not visible or predictable to the original process. This can lead to data or memory corruption, denial of service, etc.

Potential Mitigations

Related Attack Patterns

• https://cwe.mitre.org/data/definitions/25.html
• https://cwe.mitre.org/data/definitions/26.html
• https://cwe.mitre.org/data/definitions/27.html

References

• https://git.kernel.org/stable/c/4194766ec8756f4f654d595ae49962acbac49490
• https://git.kernel.org/stable/c/930e1790b99e5839e1af69d2f7fd808f1fba2df9
• https://git.kernel.org/stable/c/e9087e828827e5a5c85e124ce77503f2b81c3491