Steps to Reproduce

1. Build mono in Linux or Android in gcc with -O2
2. Test -> Socket.ReceiveBufferSize = 50000
3. try a few more times
4. You'll see random results

Current Behavior

Roll in 0-65535

Expected Behavior

be correct value

On which platforms did you notice this

[ ] macOS
[x ] Linux and android build by unity
[ ] Windows

Version Used:

all

Stacktrace

int _wapi_setsockopt(guint32 fd, int level, int optname,
const void *optval, socklen_t optlen)
{
....
* int bufsize = *((int *) optval); //is undefined behaviour
}