Jeff Layton 641e5e2085 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. Fixes: 1da177e4c3 ("Linux-2.6.12-rc2") Cc: stable@vger.kernel.org Assisted-by: Claude:claude-opus-4-8 Signed-off-by: Jeff Layton <jlayton@kernel.org> Link: https://patch.msgid.link/20260611-nfsd-testing-v2-16-5b90e276f2d9@kernel.org Signed-off-by: Chuck Lever <cel@kernel.org>		2026-08-10 09:54:35 -04:00
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bind.h	lockd, nfsd: RCU-protect nlmsvc_ops dispatch	2026-08-10 09:54:35 -04:00