diff --git a/sys/kern/kern_sig.c b/sys/kern/kern_sig.c
index 05d0c5bed961..c1ed0ffda291 100644
--- a/sys/kern/kern_sig.c
+++ b/sys/kern/kern_sig.c
@@ -2012,8 +2012,10 @@ coredump(struct thread *td)
 	}
 	VATTR_NULL(&vattr);
 	vattr.va_size = 0;
+	vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td);
 	VOP_LEASE(vp, td, cred, LEASE_WRITE);
 	VOP_SETATTR(vp, &vattr, cred, td);
+	VOP_UNLOCK(vp, 0, td);
 	PROC_LOCK(p);
 	p->p_acflag |= ACORE;
 	PROC_UNLOCK(p);