If a bad header is received from the client or the connection is broken,

send an internal VM_DISPOSE command to shut down the debugger thread
properly.  This prevents runtime hangs that occur during profile
events after the debugger shuts down.

Author: Brian Raderman

mono/mini/debugger-agent.c

@@ -12015,17 +12015,21 @@ debugger_thread (void *arg)
 		/* This will break if the socket is closed during shutdown too */
 		if (res != HEADER_LENGTH) {
 			DEBUG_PRINTF (1, "[dbg] transport_recv () returned %d, expected %d.\n", res, HEADER_LENGTH);
-			break;
-		}
-
-		p = header;
-		end = header + HEADER_LENGTH;
+			len = HEADER_LENGTH;
+			id = 0;
+			flags = 0;
+			command_set = CMD_SET_VM;
+			command = CMD_VM_DISPOSE;
+		} else {
+			p = header;
+			end = header + HEADER_LENGTH;
 
-		len = decode_int (p, &p, end);
-		id = decode_int (p, &p, end);
-		flags = decode_byte (p, &p, end);
-		command_set = (CommandSet)decode_byte (p, &p, end);
-		command = decode_byte (p, &p, end);
+			len = decode_int (p, &p, end);
+			id = decode_int (p, &p, end);
+			flags = decode_byte (p, &p, end);
+			command_set = (CommandSet)decode_byte (p, &p, end);
+			command = decode_byte (p, &p, end);
+		}
 
 		g_assert (flags == 0);