net: ipv6: Fix crash from fragmented packets

Echo server crashes upon reception of fragmented packets. This
occurs when fragmentation is enabled with the default prj.conf
of echo server. The cause is that by default with logs disabled
net_sprint_ipv6_addr returns NULL.

Signed-off-by: Ruslan Mstoi <[email protected]>

Author: Ruslan Mstoi

subsys/net/ip/ipv6.c

@@ -3268,10 +3268,12 @@ static bool reassembly_cancel(u32_t id,
 
 static void reassembly_info(char *str, struct net_ipv6_reassembly *reass)
 {
-	char out[NET_IPV6_ADDR_LEN];
 	int i, len;
 
+#if NET_LOG_ENABLED > 0
+	char out[NET_IPV6_ADDR_LEN];
 	snprintk(out, sizeof(out), "%s", net_sprint_ipv6_addr(&reass->dst));
+#endif
 
 	for (i = 0, len = 0; i < NET_IPV6_FRAGMENTS_MAX_PKT; i++) {
 		if (!reass->pkt[i]) {