diff --git a/usr.sbin/kgmon/kgmon.c b/usr.sbin/kgmon/kgmon.c
index 386d3956b35a..17f59cdd9ee2 100644
--- a/usr.sbin/kgmon/kgmon.c
+++ b/usr.sbin/kgmon/kgmon.c
@@ -511,6 +511,7 @@ reset(struct kvmvars *kvp)
 		if (kvm_write(kvp->kd, (u_long)kvp->gpm.tos, zbuf,
 		    kvp->gpm.tossize) != (ssize_t)kvp->gpm.tossize)
 			errx(15, "tos zero: %s", kvm_geterr(kvp->kd));
+		free(zbuf);
 		return;
 	}
 	(void)seteuid(0);