--- ./src/emacs.c~ 2021-12-24 16:44:24.693460891 +0100 +++ ./src/emacs.c 2021-12-24 23:09:28.461964680 +0100 @@ -2462,13 +2462,13 @@ reset_all_sys_modes (); if (sig && sig != SIGTERM) { - static char const fmt[] = "Fatal error %d: %n%s\n"; - char buf[max ((sizeof fmt - sizeof "%d%n%s\n" + static char const fmt[] = "Fatal error %d: %s\n"; + char buf[max ((sizeof fmt - sizeof "%d%s\n" + INT_STRLEN_BOUND (int) + 1), min (PIPE_BUF, MAX_ALLOCA))]; char const *sig_desc = safe_strsignal (sig); int nlen; - int buflen = snprintf (buf, sizeof buf, fmt, sig, &nlen, sig_desc); + int buflen = snprintf (buf, sizeof buf, fmt, sig, sig_desc); if (0 <= buflen && buflen < sizeof buf) emacs_write (STDERR_FILENO, buf, buflen); else