CVE-2026-80813: nvmet: fix NULL pointer dereference in nvmet_execute_identify_nslist()

In the Linux kernel, the following vulnerability has been resolved: nvmet: fix NULL pointer dereference in nvmet_execute_identify_nslist() When a host issues an Identify command with CNS 07h (Active Namespace ID List for a specific I/O Command Set), nvmet_execute_identify_nslist() is called with match_css set. The command-set filter dereferences req->ns, but this handler never calls nvmet_req_find_ns(), so req->ns is always NULL (nvmet_req_init() resets it to NULL). As soon as an enabled namespace with an NSID greater than the requested value exists, req->ns->csi dereferences a NULL pointer and oopses. Besides the crash, the comparison is logically wrong: to filter the list by command set it must test the command set of the namespace being iterated, not a single fixed value. Use the loop variable ns->csi.