Out of curiosity I wrote this program, which uses the syscalls of Linux and only should work on it: .section .text .global _start
_start: mov $1, %rax mov $1, %rdi mov $MSG_Hello, %rsi mov $LEN_Hello, %rdx syscall mov $60, %rax mov $0, %rdi syscall .section .data MSG_Hello: .ascii "Hello, world!\n" .set LEN_Hello, . - MSG_Hello I built the program and ran it like so: $ as -g program.S -o prorgam.o $ ld -g program.o -o program $ gdb program (gdb) break start (gdb) run (gdb) next 5 At this point, a double fault evidently happens, Mach starts panicking, and the registers are dumped: * RAX=4010DE * RBX=0 * RCX=1 * RDX=0 * RSI=0 * RDI=0 * RBP=0 * RSP=0 * R8 to R12=0 * EFLAGS=4000CE The error message is: `trapno 0: Divide error, error 01402ff8' `panic ../i386/i386/trap.c:677: handle_double_fault: DOUBLE FAULT! This is critical' I'm using QEMU with these args: `-M q35 -m 8G' When not using GDB, the program is simply killed by the system and nothing bad seems to happen. I'm guessing Linux syscalls need not be the same as Mach syscalls, but a double fault from some faulty program shouldn't trigger a panic without even root privileges. * OS: Debian GNU/Hurd for x86_64, installed through the latest netinst CD * Toolchain: GNU Binutils 2.43.1, GDB 13.2-1+hurd.3 "Kun nykyaikainen tietokone vahingossa hävittää kaiken, mitä olet kirjoittanut, mitä teet? Sisäistät vihan. Tunget sen sisällesi. [...] Kohtelet ongelman lähdettä kuin kuningasta." – Zach Weinersmith
