abis_rsl_rx_dchan(): guard against lchan_lookup() returning NULL
Found this by coincidence, no actual failure case was observed.
lchan_lookup() does have a return NULL code path, so we should not blindly use
its returned pointer.
Change-Id: I34ce126d36420b8194c88c0faa865294334a6658
diff --git a/openbsc/src/libbsc/abis_rsl.c b/openbsc/src/libbsc/abis_rsl.c
index dc4ede2..316fc3f 100644
--- a/openbsc/src/libbsc/abis_rsl.c
+++ b/openbsc/src/libbsc/abis_rsl.c
@@ -1456,6 +1456,8 @@
msg->lchan = lchan_lookup(sign_link->trx, rslh->chan_nr,
"Abis RSL rx DCHAN: ");
+ if (!msg->lchan)
+ return -1;
ts_name = gsm_lchan_name(msg->lchan);
switch (rslh->c.msg_type) {