CVE-2026-89709lockd, nfsd: RCU-protect nlmsvc_ops dispatch

Official description

In the Linux kernel, the following vulnerability has been resolved: lockd, nfsd: RCU-protect nlmsvc_ops dispatch nlmsvc_ops is published by nfsd_lockd_init() and cleared by nfsd_lockd_shutdown() with plain stores, while lockd dereferences it unguarded from dispatch sites in fs/lockd/svcsubs.c. The pointer targets nfsd's .rodata and the fopen/fclose callbacks live in nfsd's .text, so a stale load after rmmod nfsd results in either a NULL deref or a module-text use-after-free. Declare nlmsvc_ops as __rcu, publish via rcu_assign_pointer(), clear via RCU_INIT_POINTER() + synchronize_rcu(). Add a struct module *owner field to nlmsvc_binding and pin the module across indirect calls with try_module_get/module_put. When the binding is torn down, fall back to fput() to avoid leaking struct file references.

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/cc2f0d79b21be69b891cbd1899daf2a1fdf9df87
• https://git.kernel.org/stable/c/43943532c105ea8fe26039a1347cfda4ac0fcadc
• https://git.kernel.org/stable/c/6e7495972039f212e336e552b58cac9dd54611c3
• https://git.kernel.org/stable/c/836ce2b99bcce6d68c58edd04efbc5cd1fd581af
• https://git.kernel.org/stable/c/3c461a1820088fb5889d73a6522369bde45527a9
• https://git.kernel.org/stable/c/641e5e20852359b8c31149be4598884e30652f60