sys/cnmac: fix command buffer leak on transmit failure

visa@,

my ER-4 whcih I used as router had reached interesting state: it floods
errors like this:

Jun 30 11:11:39 gw /bsd: cnmac2: cannot allocate command buffer from free pool allocator
Jun 30 11:11:39 gw /bsd: cnmac2: failed to transmit packet
Jun 30 11:11:40 gw /bsd: cnmac2: cannot allocate command buffer from free pool allocator
Jun 30 11:11:40 gw /bsd: cnmac2: failed to transmit packet

tons of them, I have no idea what had happened before I discovered it in
that state, but device was ok via serial, but network was dead.

After reading code near that error I think I had spotted a leak.

Am I right?

Index: sys/arch/octeon/dev/if_cnmac.c
===================================================================
RCS file: /home/cvs/src/sys/arch/octeon/dev/if_cnmac.c,v
diff -u -p -r1.91 if_cnmac.c
--- sys/arch/octeon/dev/if_cnmac.c	19 Jun 2026 15:12:10 -0000	1.91
+++ sys/arch/octeon/dev/if_cnmac.c	8 Jul 2026 22:20:34 -0000
@@ -918,9 +918,6 @@ cnmac_send_cmd(struct cnmac_softc *sc, u
 
 	OCTEON_ETH_KASSERT(cmdptr != NULL);
 
-	*cmdptr++ = pko_cmd_w0;
-	*cmdptr++ = pko_cmd_w1;
-
 	OCTEON_ETH_KASSERT(sc->sc_cmdptr.cmdptr_idx + 2 <= FPA_COMMAND_BUFFER_POOL_NWORDS - 1);
 
 	if (sc->sc_cmdptr.cmdptr_idx + 2 == FPA_COMMAND_BUFFER_POOL_NWORDS - 1) {
@@ -934,10 +931,14 @@ cnmac_send_cmd(struct cnmac_softc *sc, u
 			result = 1;
 			goto done;
 		}
+		*cmdptr++ = pko_cmd_w0;
+		*cmdptr++ = pko_cmd_w1;
 		*cmdptr++ = buf;
 		sc->sc_cmdptr.cmdptr = (uint64_t)buf;
 		sc->sc_cmdptr.cmdptr_idx = 0;
 	} else {
+		*cmdptr++ = pko_cmd_w0;
+		*cmdptr++ = pko_cmd_w1;
 		sc->sc_cmdptr.cmdptr_idx += 2;
 	}
 


-- 
wbr, Kirill