SendZeroCopy closes the message when zmq_msg_send fails, and closing a
message built with zmq_msg_init_data runs its free function - here
zmq_socket_free, which already calls release(). The writer thread then
released the same slot a second time, under a comment claiming the
callback would not run.
The second release put a slot back on the free list while the receiver
had already taken it for the next image, so two threads wrote the same
buffer and the sending/preparation counters drifted permanently.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
leonarski_fandClaude Opus 5
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