Linux Kernel CVE-2025-40343

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

nvmet-fc: avoid scheduling association deletion twice

When forcefully shutting down a port via the configfs interface, nvmet_port_subsys_drop_link() first calls nvmet_port_del_ctrls() and then nvmet_disable_port(). Both functions will eventually schedule all remaining associations for deletion.

The current implementation checks whether an association is about to be removed, but only after the work item has already been scheduled. As a result, it is possible for the first scheduled work item to free all resources, and then for the same work item to be scheduled again for deletion.

Because the association list is an RCU list, it is not possible to take a lock and remove the list entry directly, so it cannot be looked up again. Instead, a flag (terminating) must be used to determine whether the association is already in the process of being deleted.

The vulnerability affects the Linux kernel's nvmet-fc target driver across multiple stable branches, as evidenced by six backport commits on git.kernel.org (04d17540ef51, 2f4852db87e2, 601ed47b2363, 85e2ce1920cb, c09ac9a63fc3, f2537be4f842). No specific CPE strings or exact version ranges were provided in the input, so precise affected kernel version numbers are not independently confirmed here; only systems that build and load the nvmet-fc module and configure an NVMe-over-Fibre-Channel target are exposed. The authoritative fix references are the stable-tree commits at https://git.kernel.org/stable/c/2f4852db87e25d4e226b25cb6f652fef9504360e and its sibling backports.