Application getting segfault and signal 134 when i send mqtt messages to cloud 5 times per second continously. about paho.mqtt.c HOT 5 CLOSED

Closing this issue as I didn't get a response to my last question.

from paho.mqtt.c.

Hey guys..

I ran into same issue mentioned here. This issue occurs after SSL_write() in SSLSocket_putdatas() fails, paho adds failed write to the "writes" list which should be written later through SSLSocket_continueWrite() function. If paho client gets disconnected before SSLSocket_continueWrite() finishes its job, SSLSocket_close() will free same SSL structure (net->ssl) which is added in"writes" list SSLSocket_putdatas. When paho reconnects and tries to finish write from "writes" list in SSLSocket_continueWrite(), crash usually occurs in SSL_write(pw->ssl,...) bcs passed argument "pw->ssl" is actually freed SSL structure pointer from SSLSocket_close() which is freed when disconnection occurred. So, now pw->ssl structure fields now contain some random values which cause app to crash mostly with SIGSEGV while dereferencing ((int*)pw->ssl)[2].. sometimes also with SIGBUS, SIGILL or memory leak occurs and app freezes at some point... depends on new random values in pw->ssl...

I simply added SocketBuffer_writeComplete(net->socket) in SSLSocket_close() which fixed this issue.. Not sure if that's best possible solution though but removing that unfinished write from a list prevented app to crash for me at least....
Also, I haven't mentioned that we are using QoS1..

Best Regards,
Goran

from paho.mqtt.c.

I'll reopen as a result of Goran's comment.

from paho.mqtt.c.

Added

SocketBuffer_writeComplete(socket);

to SocketBuffer_cleanup() which is called by Socket_close();

from paho.mqtt.c.

Fix added to the develop branch.

from paho.mqtt.c.