--- src/auth/mech-winbind.c

+++ src/auth/mech-winbind.c

@@ -187,12 +187,18 @@

 	request->continued = FALSE;

 	while ((answer = i_stream_read_next_line(in_pipe)) == NULL) {

-		if (in_pipe->stream_errno != 0)

+		if (in_pipe->stream_errno != 0 || in_pipe->eof)

 			break;

 	}

 	if (answer == NULL) {

-		auth_request_log_error(auth_request, AUTH_SUBSYS_MECH,

-				       "read(in_pipe) failed: %m");

+		if (in_pipe->stream_errno != 0) {

+			auth_request_log_error(auth_request, AUTH_SUBSYS_MECH,

+					       "read(in_pipe) failed: %m");

+		} else {

+			auth_request_log_error(auth_request, AUTH_SUBSYS_MECH,

+					       "read(in_pipe) failed: "

+					       "unexpected end of file");

+		}

 		return HR_RESTART;

 	}