CVE-2022-49371

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.

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/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