untrusted comment: verify with openbsd-79-base.pub
RWTSdNN9A3yvWCiOWpdv75TXDVX8IxepOIdgTPfkyg8lZRB5R6AhontF2U3LSPK0Y8vZKOOuJZPYM6Yj+ugaYdW5e06+KEdCHQA=

OpenBSD 7.9 errata 043, November 5, 2026:

If pf is configured with FQ-CoDel queueing, sustained traffic
overloading a queue could wrap a drop counter and disturb queue
management.

Apply by doing:
    signify -Vep /etc/signify/openbsd-79-base.pub -x 043_pffq.patch.sig \
        -m - | (cd /usr/src && patch -p0)

And then rebuild and install a new kernel:
    KK=`sysctl -n kern.osversion | cut -d# -f1`
    cd /usr/src/sys/arch/`machine`/compile/$KK
    make obj
    make config
    make
    make install

Index: sys/net/fq_codel.c
===================================================================
RCS file: /cvs/src/sys/net/fq_codel.c,v
diff -u -p -r1.20 fq_codel.c
--- sys/net/fq_codel.c	14 Mar 2026 00:10:38 -0000	1.20
+++ sys/net/fq_codel.c	26 Oct 2026 17:08:48 -0000
@@ -459,7 +459,16 @@ codel_dequeue(struct codel *cd, struct c
 		case DROPPING:
 			m = codel_commit(cd, m);
 			ml_enqueue(free_ml, m);
-			cd->drops++;
+
+			/*
+			 * Prevent counter wrap. Once drops saturates, lower
+			 * ldrops to preserve the delta for grace-period reuse,
+			 * until the delta itself saturates
+			 */
+			if (cd->drops < USHRT_MAX)
+				cd->drops++;
+			else if (cd->ldrops > 0)
+				cd->ldrops--;
 
 			*dpkts += 1;
 			*dbytes += m->m_pkthdr.len;