VTY: fix NULL-pointer dereference in 'show transceiver'

Change-Id: I403a027f064a4898eb74a11381bab3c884ec8ccf
---
M src/osmo-bts-trx/trx_vty.c
1 file changed, 5 insertions(+), 0 deletions(-)

diff --git a/src/osmo-bts-trx/trx_vty.c b/src/osmo-bts-trx/trx_vty.c
index bd6b3b1..70e9b36 100644
--- a/src/osmo-bts-trx/trx_vty.c
+++ b/src/osmo-bts-trx/trx_vty.c
@@ -89,11 +89,16 @@
 		else
 			vty_out(vty, " bsic   : undefined%s", VTY_NEWLINE);
 
+		/* trx->ts[tn].priv is NULL in absence of the A-bis connection */
+		if (trx->rsl_link == NULL)
+			continue;
+
 		for (tn = 0; tn < ARRAY_SIZE(trx->ts); tn++) {
 			const struct gsm_bts_trx_ts *ts = &trx->ts[tn];
 			const struct l1sched_ts *l1ts = ts->priv;
 			const struct trx_sched_multiframe *mf;
 
+			OSMO_ASSERT(l1ts != NULL);
 			mf = &trx_sched_multiframes[l1ts->mf_index];
 
 			vty_out(vty, "  timeslot #%u (%s)%s",

