CVE-2022-49371 Information

Description

In the Linux kernel the following vulnerability has been resolved:

driver core: fix deadlock in __device_attach

In __device_attach function The lock holding logic is as follows: … __device_attach device_lock(dev) // get lock dev async_schedule_dev(__device_attach_async_helper dev); // func async_schedule_node async_schedule_node_domain(func) entry = kzalloc(sizeof(struct async_entry) GFP_ATOMIC); / when fail or work limit sync to execute func but __device_attach_async_helper will get lock dev as well which will lead to A-A deadlock. / if (!entry || atomic_read(&entry_count) > MAX_WORK) func; else queue_work_node(node system_unbound_wq &entry->work) device_unlock(dev)

As shown above when it is allowed to do async probes because of out of memory or work limit async work is not allowed to do sync execute instead. it will lead to A-A deadlock because of __device_attach_async_helper getting lock dev.

To fix the deadlock move the async_schedule_dev outside device_lock as we can see in async_schedule_node_domain the parameter of queue_work_node is system_unbound_wq so it can accept concurrent operations. which will also not change the code logic and will not lead to deadlock.

Reference

https://git.kernel.org/stable/c/34fdd9b7def9d2fcb71bb7b0bc4848dd7313767e https://git.kernel.org/stable/c/36ee9ffca8ef56c302f2855c4a5fccf61c0c1ada https://git.kernel.org/stable/c/593b595332bd2d65e1a5c1ae7897996c157f5468 https://git.kernel.org/stable/c/b232b02bf3c205b13a26dcec08e53baddd8e59ed https://git.kernel.org/stable/c/d53a227bfcd5160ce1b61d9954901968a20651e7 https://git.kernel.org/stable/c/df6de52b80aa3b46f5ac804412355ffe2e1df93e