Abort signal thrown from zmq_send

[raghav-sesh]

The following is the string I'm trying to send as a message using zmq_send:
" Node[0]TC[0]: Thread tid 16814, cpu 14 started"

Intermittently, my program crashes only while sending this message, not for other messages. This string is generated using snprintf, so it is definitely NULL terminated.

Following is the stack trace of the crash:

#0 0x00007fa29b56d187 in raise () from /lib64/libc.so.6
#1 0x00007fa29b56e538 in abort () from /lib64/libc.so.6
#2 0x00007fa29ca9ba3e in zmq::zmq_abort(char const*) ()
from libzmq.so.4.2.0
#3 0x00007fa29caa4389 in zmq::msg_t::size() ()
from libzmq.so.4.2.0
#4 0x00007fa29cad1032 in zmq::v2_encoder_t::message_ready() ()
fromlibzmq.so.4.2.0
#5 0x00007fa29cac4801 in zmq::stream_engine_t::out_event() ()
from libzmq.so.4.2.0
#6 0x00007fa29ca9c8a4 in zmq::io_thread_t::in_event() ()
from libzmq.so.4.2.0
#7 0x00007fa29ca9b71e in zmq::epoll_t::loop() ()
from libzmq.so.4.2.0
#8 0x00007fa29cace915 in thread_routine ()
from libzmq.so.4.2.0
#9 0x00007fa2a18ec0a4 in start_thread () from /lib64/libpthread.so.0
#10 0x00007fa29b61d04d in clone () from /lib64/libc.so.6

I have reproduced the same with two version of zmq - 4.2.0 and 4.1.6.

[bluca]

What does the code look like? Do you have a minimal repro snippet?

[raghav-sesh]

@bluca
It looks something like this:
char strLogMsg[256];
sprintf(strLogMsg, "Node[%d]TC[%d]: Thread tid %d, cpu %d started", NodeID_, tcID, tid, cpunum);
int rc = zmq_send(publisher,strLogMsg,strlen(strLogMsg)+1,0);

[bluca]

Are you sure the buffer is large enough? It might be overflowing

[raghav-sesh]

It is large enough. Data size is only 46 bytes. But the container is created of size 256 bytes. It's an intermittent problem. Fails 50% of the time.

[raghav-sesh]

@bluca
I'm seeing a new stack trace as well:

(gdb) bt
#0 0x00007f2361cad187 in raise () from /lib64/libc.so.6
#1 0x00007f2361cae538 in abort () from /lib64/libc.so.6
#2 0x00007f23631c06e9 in zmq::zmq_abort(char const*) ()
from libzmq.so
#3 0x00007f23631c83cd in zmq::msg_t::add_refs(int) ()
from libzmq.so
#4 0x00007f23631bf943 in zmq::dist_t::distribute(zmq::msg_t*) ()
from libzmq.so
#5 0x00007f23631bfab2 in zmq::dist_t::send_to_matching(zmq::msg_t*) ()
from libzmq.so
#6 0x00007f23631eff81 in zmq::xpub_t::xsend(zmq::msg_t*) ()
from libzmq.so
#7 0x00007f23631daed2 in zmq::socket_base_t::send(zmq::msg_t*, int) ()
from libzmq.so
#8 0x00007f23631f2f2e in zmq_send ()
from libzmq.so
#9 0x00007f2366c7e5aa in postLog (
this=0x2872568, messageSize=47,
message=0x7f1fb06436c0 "Node[0]TC[0]: Thread tid 31032, cpu 14 started")

[bjovke]

First of all, you should not use sprintf() in your program AT ALL. Instead snprintf() should be always used, like this:

char strLogMsg[256];
snprintf(strLogMsg, 256, "Node[%d]TC[%d]: Thread tid %d, cpu %d started", NodeID_, tcID, tid, cpunum);
int rc = zmq_send(publisher,strLogMsg,strlen(strLogMsg)+1,0);

After you do it like this and the issue is still present then it could be discussed if there's something wrong with zmq_send().

[sigiesec]

Closing this due to inactivity. If you still have problems, please reopen and provide some more information on how to reproduce it, an executable test case would be best.