Index: share/man/man9/rmlock.9
===================================================================
--- share/man/man9/rmlock.9
+++ share/man/man9/rmlock.9
@@ -186,6 +186,9 @@
 has not been initialized multiple times without intervening calls to
 .Fn rm_destroy
 unless this option is specified.
+.It Dv RM_DUPOK
+.Xr witness 4
+should not log messages about duplicate locks being acquired.
 .El
 .It Fn rm_rlock "struct rmlock *rm" "struct rm_priotracker* tracker"
 Lock
Index: sys/kern/kern_rmlock.c
===================================================================
--- sys/kern/kern_rmlock.c
+++ sys/kern/kern_rmlock.c
@@ -289,6 +289,8 @@
 		liflags |= LO_RECURSABLE;
 	if (opts & RM_NEW)
 		liflags |= LO_NEW;
+	if (opts & RM_DUPOK)
+		liflags |= LO_DUPOK;
 	rm->rm_writecpus = all_cpus;
 	LIST_INIT(&rm->rm_activeReaders);
 	if (opts & RM_SLEEPABLE) {
Index: sys/sys/rmlock.h
===================================================================
--- sys/sys/rmlock.h
+++ sys/sys/rmlock.h
@@ -48,6 +48,7 @@
 #define	RM_RECURSE	0x00000002
 #define	RM_SLEEPABLE	0x00000004
 #define	RM_NEW		0x00000008
+#define	RM_DUPOK	0x00000010
 
 void	rm_init(struct rmlock *rm, const char *name);
 void	rm_init_flags(struct rmlock *rm, const char *name, int opts);