CVE-2023-53116: Use After Free

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

nvmet: avoid potential UAF in nvmet_req_complete()

An nvme target ->queue_response() operation implementation may free the request passed as argument. Such implementation potentially could result in a use after free of the request pointer when percpu_ref_put() is called in nvmet_req_complete().

Avoid such problem by using a local variable to save the sq pointer before calling __nvmet_req_complete(), thus avoiding dereferencing the req pointer after that function call.