I should also note that on the very last invocation before the crash, a message about failure to parse Call-ID appeared in the logs, even though there was a Call-ID header there -- same as on the previous requests.
Jan 7 02:37:43 localhost /usr/local/sbin/kamailio[3154]: INFO: [R-XHTTP-REQUEST:abc123] -> Handling JSON RPC request: /csrp_rpc/ Jan 7 02:37:45 localhost /usr/local/sbin/kamailio[3146]: INFO: [R-XHTTP-REQUEST:abc123] -> Handling JSON RPC request: /csrp_rpc/ Jan 7 02:37:46 localhost /usr/local/sbin/kamailio[3154]: INFO: [R-XHTTP-REQUEST:abc123] -> Handling JSON RPC request: /csrp_rpc/ Jan 7 02:37:46 localhost /usr/local/sbin/kamailio[3146]: INFO: [R-XHTTP-REQUEST:abc123] -> Handling JSON RPC request: /csrp_rpc/ Jan 7 02:37:47 localhost /usr/local/sbin/kamailio[3154]: INFO: [R-XHTTP-REQUEST:abc123] -> Handling JSON RPC request: /csrp_rpc/ Jan 7 02:37:47 localhost /usr/local/sbin/kamailio[3149]: INFO: [R-XHTTP-REQUEST:abc123] -> Handling JSON RPC request: /csrp_rpc/ Jan 7 02:37:47 localhost /usr/local/sbin/kamailio[3154]: INFO: [R-XHTTP-REQUEST:abc123] -> Handling JSON RPC request: /csrp_rpc/ Jan 7 02:37:47 localhost /usr/local/sbin/kamailio[3149]: INFO: [R-XHTTP-REQUEST:abc123] -> Handling JSON RPC request: /csrp_rpc/ Jan 7 02:37:47 localhost /usr/local/sbin/kamailio[3154]: INFO: [R-XHTTP-REQUEST:abc123] -> Handling JSON RPC request: /csrp_rpc/ Jan 7 02:37:48 localhost /usr/local/sbin/kamailio[3149]: INFO: [R-XHTTP-REQUEST:abc123] -> Handling JSON RPC request: /csrp_rpc/ Jan 7 02:37:48 localhost /usr/local/sbin/kamailio[3150]: ERROR: pv [pv_core.c:667]: pv_get_callid(): cannot parse Call-Id header Jan 7 02:37:48 localhost /usr/local/sbin/kamailio[3150]: INFO: [R-XHTTP-REQUEST:<null>] -> Handling JSON RPC request: /csrp_rpc/ Jan 7 02:37:48 localhost /usr/local/sbin/kamailio[3154]: INFO: [R-XHTTP-REQUEST:abc123] -> Handling JSON RPC request: /csrp_rpc/ Jan 7 02:37:48 localhost /usr/local/sbin/kamailio[3101]: ALERT: <core> [main.c:784]: handle_sigs(): child process 3150 exited by a signal 11 Jan 7 02:37:48 localhost /usr/local/sbin/kamailio[3101]: ALERT: <core> [main.c:787]: handle_sigs(): core was generated Jan 7 02:37:48 localhost /usr/local/sbin/kamailio[3101]: INFO: <core> [main.c:799]: handle_sigs(): terminating due to SIGCHLD