The problem was in the test. I didn't allocate the memory for output parameter. But runtime was wrong with the line of code

Crash reproduced on a smaller range. I don't call any system call here, so the problem supposed to be located

Loop is now just listening, there's writer, errorHandler goroutines and a handler goroutine per request

Loop is now just listening, there's writer, errorHandler goroutines and a handler goroutine per request