CVE-2025-40231

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> vsock: fix lock inversion in vsock_assign_transport()<br /> <br /> Syzbot reported a potential lock inversion deadlock between<br /> vsock_register_mutex and sk_lock-AF_VSOCK when vsock_linger() is called.<br /> <br /> The issue was introduced by commit 687aa0c5581b ("vsock: Fix<br /> transport_* TOCTOU") which added vsock_register_mutex locking in<br /> vsock_assign_transport() around the transport-&gt;release() call, that can<br /> call vsock_linger(). vsock_assign_transport() can be called with sk_lock<br /> held. vsock_linger() calls sk_wait_event() that temporarily releases and<br /> re-acquires sk_lock. During this window, if another thread hold<br /> vsock_register_mutex while trying to acquire sk_lock, a circular<br /> dependency is created.<br /> <br /> Fix this by releasing vsock_register_mutex before calling<br /> transport-&gt;release() and vsock_deassign_transport(). This is safe<br /> because we don&amp;#39;t need to hold vsock_register_mutex while releasing the<br /> old transport, and we ensure the new transport won&amp;#39;t disappear by<br /> obtaining a module reference first via try_module_get().