Why does `QWebSocket` hang upon receiving a specific `binaryMessageReceived()` signal

[iammilind]

We are facing an extremely strange issue which is prevalent in Qt6.2 & Qt6.5.

A `QWebSocketServer` is running in Windows server OS. Browser connects via WebSockets to this server. The client from the browser sends data filled with *any* file content (text or image) of few 100 KBs in form of a protobuf.
All the browsers in various devices including Windows, MacOS, Android, Linux etc. work fine.

Now one person brought a particular MacOS machine (Mojave 10.14.1). **Only with this MacOS if the same protobuf message is sent then the whole Server hangs**!!!
We are stunned that how is that even possible? The `QWebSocket::binaryMessageReceived()` is not called and the CPU utilization goes from usual <1% to 50% and even 99%, sabotaging the whole OS.

This issue reproduces with MSVC & MinGW(64 bit) both. We even tried pausing this in debugger mode. This shows a stack frame where at last `SslLoadCertificate()` finally calls `SslGetServerIdentity()` in the suspicious thread. But why is this invoked is not clear as the connection is already established and several messages are exchanged already.

Couldn't find any such problem anywhere. Any pointer will be useful.

https://stackoverflow.com/questions/...sagereceived-s

[iammilind]

The issue got fixed after we downgraded Qt6.5 to Qt6.2. After that hang transformed into an `internalSslError()`.

The issue was due to "Windows Secure Channel" coming along with Qt6.5. With Qt6.2, we were able to link the OpenSSL 1.1.1.