seg fault on dsm_create call

Some debug info related to my previous post -

* thread #1: tid = 0x2601e9, 0x0000000100313e5e 
postgres`ResourceOwnerEnlargeDSMs + 10, queue = 'com.apple.main-thread', 
stop reason = EXC_BAD_ACCESS (code=1, address=0x130)  * frame #0: 0x0000000100313e5e postgres`ResourceOwnerEnlargeDSMs
+10    frame #1: 0x0000000100202a5f postgres`dsm_create_descriptor + 22    frame #2: 0x0000000100202853
postgres`dsm_create+ 43    frame #3: 0x0000000101a17717 pg_mystem.so`_PG_init + 39
 


Hello,
sorry for my repost from psql-novice, probably it was not a right place 
for my question.

I'm trying to understand how to work with dynamic shared memory, message 
queues and workers.
The problem is I can not initialize any dsm segment -
     void _PG_init() {         ...         dsm_segment *seg = dsm_create(32768, 0); // Segmentation fault 
here         ...         BackgroundWorker worker;         sprintf(worker.bgw_name, "mystem wrapper process");
worker.bgw_flags= BGWORKER_SHMEM_ACCESS;         worker.bgw_start_time = BgWorkerStart_RecoveryFinished;
worker.bgw_restart_time= BGW_NEVER_RESTART;         worker.bgw_main = mainProc;         worker.bgw_notify_pid = 0;
  RegisterBackgroundWorker(&worker);     }
 

Also I was trying to move dsm_create call to a worker, but with the same 
result -
     static void mainProc(Datum) {         ...         dsm_segment *seg = dsm_create(32768, 0); // Segmentation fault 
here         ...         pqsignal(SIGTERM, mystemSigterm);         BackgroundWorkerUnblockSignals();         ...

What could be a reason and what am I doing wrong?

PS
test/modules/test_shm_mq works fine...
dynamic_shared_memory_type = posix
OSX 10.11.5
PostgreSQL 9.5.3

-- 
Best regards,
Max Fomichev