Affected: Linux

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

wifi: rt2x00: avoid full teardown before work setup in probe

rt2x00lib_probe_dev() uses the full rt2x00lib_remove_dev() teardown for all probe failures. However, drv_data allocation and workqueue allocation can fail before intf_work, autowakeup_work and sleep_work have been initialized.

Do not enter the full remove path until the probe has reached the point where those work items are set up. Return directly for drv_data allocation failure, and use a small early cleanup path for workqueue allocation failure.

This issue was found by our static analysis tool and then confirmed by manual review of rt2x00lib_probe_dev() and rt2x00lib_remove_dev(). The early probe exits should not call a common teardown path that assumes the later work setup has already completed.

A QEMU PoC forced alloc_ordered_workqueue() to fail before the work initializers are reached. The resulting fail path entered rt2x00lib_remove_dev(), and DEBUG_OBJECTS reported invalid work drains with rt2x00lib_probe_dev() and rt2x00lib_remove_dev() in the stack.