Program terminated with signal 11, Segmentation fault.
#0  0x0000000000422ddb in userdb_blocking_iter_deinit (_ctx=0x17b59360) at userdb-blocking.c:120
120		int ret = ctx->ctx.failed ? -1 : 0;
(gdb) bt
#0  0x0000000000422ddb in userdb_blocking_iter_deinit (_ctx=0x17b59360) at userdb-blocking.c:120
#1  0x000000000040c812 in master_input_list_callback (user=0x0, context=0x17b59350) at auth-master-connection.c:322
#2  0x0000000000422c8d in iter_callback (reply=0x17b38248 "FAIL\t-1", context=0x17b96ef8) at userdb-blocking.c:78
#3  0x0000000000415a71 in auth_worker_destroy (_conn=0x7fffa5424718, reason=0x42feef "Lookup timed out", restart=true) at auth-worker-server.c:197
#4  0x0000000000415416 in auth_worker_call_timeout (conn=0x0) at auth-worker-server.c:72
#5  0x00002b97560b1755 in io_loop_handle_timeouts_real (ioloop=0x17b405e0) at ioloop.c:328
#6  0x00002b97560b17af in io_loop_handle_timeouts (ioloop=0x17b405e0) at ioloop.c:339
#7  0x00002b97560b2970 in io_loop_handler_run (ioloop=0x17b405e0) at ioloop-epoll.c:184
#8  0x00002b97560b17f5 in io_loop_run (ioloop=0x17b405e0) at ioloop.c:350
#9  0x00002b975609a93e in master_service_run (service=0x17b404b0, callback=0x4181a8 <client_connected>) at master-service.c:495
#10 0x00000000004184c1 in main (argc=1, argv=0x17b40370) at main.c:282
(gdb) print *_ctx
$1 = (struct userdb_iterate_context *) 0x0
(gdb) up
#1  0x000000000040c812 in master_input_list_callback (user=0x0, context=0x17b59350) at auth-master-connection.c:322
322			if (userdb_blocking_iter_deinit(&ctx->iter) < 0)
(gdb) print *ctx
$2 = {conn = 0x3e35152a88, userdb = 0x3e35152a88, iter = 0x0, id = 1, failed = false}
(gdb) list
317	{
318		struct master_list_iter_ctx *ctx = context;
319		int ret;
320	
321		if (user == NULL) {
322			if (userdb_blocking_iter_deinit(&ctx->iter) < 0)
323				ctx->failed = TRUE;
324	
325			do {
326				ctx->userdb = ctx->userdb->next;