(n.b. I really hate it when I forget to switch to text mode. Sorry about that!)
(Thank you to Omar for pointing out my idiocy. :-)

If you have existing queues and try to dynamically update an anchor with:

     # pfctl -a myanchor -F rules -f myanchor.rules

It will fail on any rules with 'set queue'. This patch preloads queues to fix this.

---
diff --git sbin/pfctl/pfctl.c sbin/pfctl/pfctl.c
index 96f7b9dac06..dd052bff3d7 100644
--- sbin/pfctl/pfctl.c
+++ sbin/pfctl/pfctl.c
@@ -122,6 +122,9 @@ int pfctl_call_cleartables(int, int, struct pfr_anchoritem *);
 int    pfctl_call_clearanchors(int, int, struct pfr_anchoritem *);
 int    pfctl_call_showtables(int, int, struct pfr_anchoritem *);


+/* Preload queues for dynamic anchor updates. */
+extern void pfctl_preload_queues(int dev, struct pf_qihead *qhead);
+
 const char     *clearopt;
 char           *rulesopt;
 const char     *showopt;
@@ -2970,6 +2973,12 @@ main(int argc, char *argv[])
        }


        if (rulesopt != NULL) {
+               /* Do we need to pre-load the table and queue definitions? */
+               if (anchorname[0]) {
+                       /* Preload queues for dynamic anchor updates. */
+                        pfctl_preload_queues(dev, &qspecs);
+               } /* if (working with an anchor) */
+
                if (pfctl_rules(dev, rulesopt, opts, optimize,
                    anchorname, NULL))
                        exit_val = 1;
diff --git sbin/pfctl/pfctl_queue.c sbin/pfctl/pfctl_queue.c
index 1f0d456300c..2cb362473e4 100644
--- sbin/pfctl/pfctl_queue.c
+++ sbin/pfctl/pfctl_queue.c
@@ -71,6 +71,9 @@ void                   pfctl_print_queue_nodestat(int,
 void                    update_avg(struct queue_stats *);
 char                   *rate2str(double);


+/* Preload queues for dynamic anchor updates. */
+void pfctl_preload_queues(int dev, struct pf_qihead *qhead);
+
 int
 pfctl_show_queues(int dev, const char *iface, int opts, int verbose2)
 {
@@ -285,3 +288,34 @@ rate2str(double rate)


        return (buf);
 }
+
+/* Preload queues for dynamic anchor updates. */
+void pfctl_preload_queues(int dev, struct pf_qihead *qhead)
+{
+ struct pfctl_queue_node
+   *node;   /* Transfer node. */
+ struct pfctl_qsitem
+   *qi;     /* Transfer item. */
+
+ /* Pull in the current queue definitions. */
+ pfctl_update_qstats(dev);
+
+ /* Loop through each queue. */
+ TAILQ_FOREACH(node, &qnodes, entries) {
+   /* Allocate and pre-clear a new queue item. */
+   qi = calloc(1, sizeof(*qi));
+
+   /* Check for allocation failure. */
+   if (qi == NULL)
+     err(1, "pfctl_preload_queues: calloc");
+
+   /* Copy over the existing queue specification. */
+   bcopy(&node->qs, &qi->qs, sizeof(qi->qs));
+
+   /* Initialize the child pointer. */
+   TAILQ_INIT(&qi->children);
+
+   /* Insert this into the main definition. */
+   TAILQ_INSERT_TAIL(&qspecs, qi, entries);
+ }
+} /* pfctl_preload_queues() */