diff --git a/share/man/man4/siftr.4 b/share/man/man4/siftr.4
--- a/share/man/man4/siftr.4
+++ b/share/man/man4/siftr.4
@@ -29,7 +29,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd April 7, 2022
+.Dd April 24, 2023
 .Dt SIFTR 4
 .Os
 .Sh NAME
@@ -370,8 +370,7 @@
 disable_time_secs=1238556197    disable_time_usecs=933607 \\
 num_inbound_tcp_pkts=356    num_outbound_tcp_pkts=627 \\
 total_tcp_pkts=983    num_inbound_skipped_pkts_malloc=0 \\
-num_outbound_skipped_pkts_malloc=0    num_inbound_skipped_pkts_mtx=0 \\
-num_outbound_skipped_pkts_mtx=0    num_inbound_skipped_pkts_tcb=0 \\
+num_outbound_skipped_pkts_malloc=0    num_inbound_skipped_pkts_tcb=0 \\
 num_outbound_skipped_pkts_tcb=0    num_inbound_skipped_pkts_icb=0 \\
 num_outbound_skipped_pkts_icb=0    total_skipped_tcp_pkts=0 \\
 flow_list=172.16.7.28;22-172.16.2.5;55931,
@@ -417,16 +416,6 @@
 calls.
 .El
 .Bl -tag -offset indent -width Va
-.It Va num_inbound_skipped_pkts_mtx
-Number of inbound packets that were not processed because of failure to add the
-packet to the packet processing queue.
-.El
-.Bl -tag -offset indent -width Va
-.It Va num_outbound_skipped_pkts_mtx
-Number of outbound packets that were not processed because of failure to add the
-packet to the packet processing queue.
-.El
-.Bl -tag -offset indent -width Va
 .It Va num_inbound_skipped_pkts_tcb
 Number of inbound packets that were not processed because of failure to find the
 TCP control block associated with the packet.
diff --git a/sys/netinet/siftr.c b/sys/netinet/siftr.c
--- a/sys/netinet/siftr.c
+++ b/sys/netinet/siftr.c
@@ -112,8 +112,8 @@
  * Z is bumped to mark backwards compatible changes
  */
 #define V_MAJOR		1
-#define V_BACKBREAK	2
-#define V_BACKCOMPAT	4
+#define V_BACKBREAK	3
+#define V_BACKCOMPAT	0
 #define MODVERSION	__CONCAT(V_MAJOR, __CONCAT(V_BACKBREAK, V_BACKCOMPAT))
 #define MODVERSION_STR	__XSTRING(V_MAJOR) "." __XSTRING(V_BACKBREAK) "." \
     __XSTRING(V_BACKCOMPAT)
@@ -257,9 +257,6 @@
 	/* # pkts skipped due to failed malloc calls. */
 	uint32_t nskip_in_malloc;
 	uint32_t nskip_out_malloc;
-	/* # pkts skipped due to failed mtx acquisition. */
-	uint32_t nskip_in_mtx;
-	uint32_t nskip_out_mtx;
 	/* # pkts skipped due to failed inpcb lookups. */
 	uint32_t nskip_in_inpcb;
 	uint32_t nskip_out_inpcb;
@@ -1314,16 +1311,13 @@
 		totalss.n_out = DPCPU_VARSUM(ss, n_out);
 		totalss.nskip_in_malloc = DPCPU_VARSUM(ss, nskip_in_malloc);
 		totalss.nskip_out_malloc = DPCPU_VARSUM(ss, nskip_out_malloc);
-		totalss.nskip_in_mtx = DPCPU_VARSUM(ss, nskip_in_mtx);
-		totalss.nskip_out_mtx = DPCPU_VARSUM(ss, nskip_out_mtx);
 		totalss.nskip_in_tcpcb = DPCPU_VARSUM(ss, nskip_in_tcpcb);
 		totalss.nskip_out_tcpcb = DPCPU_VARSUM(ss, nskip_out_tcpcb);
 		totalss.nskip_in_inpcb = DPCPU_VARSUM(ss, nskip_in_inpcb);
 		totalss.nskip_out_inpcb = DPCPU_VARSUM(ss, nskip_out_inpcb);
 
 		total_skipped_pkts = totalss.nskip_in_malloc +
-		    totalss.nskip_out_malloc + totalss.nskip_in_mtx +
-		    totalss.nskip_out_mtx + totalss.nskip_in_tcpcb +
+		    totalss.nskip_out_malloc + totalss.nskip_in_tcpcb +
 		    totalss.nskip_out_tcpcb + totalss.nskip_in_inpcb +
 		    totalss.nskip_out_inpcb;
 
@@ -1334,8 +1328,6 @@
 		    "num_inbound_tcp_pkts=%ju\tnum_outbound_tcp_pkts=%ju\t"
 		    "total_tcp_pkts=%ju\tnum_inbound_skipped_pkts_malloc=%u\t"
 		    "num_outbound_skipped_pkts_malloc=%u\t"
-		    "num_inbound_skipped_pkts_mtx=%u\t"
-		    "num_outbound_skipped_pkts_mtx=%u\t"
 		    "num_inbound_skipped_pkts_tcpcb=%u\t"
 		    "num_outbound_skipped_pkts_tcpcb=%u\t"
 		    "num_inbound_skipped_pkts_inpcb=%u\t"
@@ -1348,8 +1340,6 @@
 		    (uintmax_t)(totalss.n_in + totalss.n_out),
 		    totalss.nskip_in_malloc,
 		    totalss.nskip_out_malloc,
-		    totalss.nskip_in_mtx,
-		    totalss.nskip_out_mtx,
 		    totalss.nskip_in_tcpcb,
 		    totalss.nskip_out_tcpcb,
 		    totalss.nskip_in_inpcb,