UCX blocked after .sendStreamNonBlocking(sendBuffer, new SendCallback(sendBuffer, this));

[pereverges]

Describe the bug

After running for the second or third time the same program it gets blocked at the .sendStreamNonBlocking(sendBuffer, new SendCallback(sendBuffer, this)); call, it is trying to access a port that is not listening. The application then gets stuck in the send call on a progress while.

Steps to Reproduce

Using multiple threads, performing the .sendStreamNonBlocking(sendBuffer, new SendCallback(sendBuffer, this)); call
Using 1.17 UCX version
UCX_TLS=tcp UCX_NET_DEVICES=lo UCX_LOG_LEVEL=DIAG

Setup and versions

I am using linux ubuntu 20.4 with JUXC

Additional information (depending on the issue)

[1718657516.879778] [verges:58764:a] wireup_cm.c:128 UCX DIAG client ep 0x7fd095044000 failed to connect to 127.0.0.1:43008 using tcp cms
[1718657516.879912] [verges:58764:a] uct_cm.c:97 UCX DIAG resolve callback failed with error: Endpoint is not connected
[1718657516.880768] [verges:58764:0] ucp_ep.c:1768 UCX WARN disconnect failed: Endpoint is not connected
UCX: ERROR org.openucx.jucx.UcxException: Endpoint is not connected

[gleon99]

Hi @pereverges
please add more information, according to our bug report template.

[pereverges]

I have added more information.

[evgeny-leksikov]

hi @pereverges , thanks for reporting! can you share a test application which reproduces the issue?