blob: 89137cbb5c299f0915b2d1d5fa05b54add0a2153 (
plain) (
blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
|
<think>
Okay, I'm trying to figure out whether this bug is related to user-mode or system-mode in QEMU. Let's start by understanding what the problem is.
The user set up a sparc chroot on a Debian x86-64 host. They used debootstrap with --foreign and then tried to run the second stage inside the chroot using qemu-sparc32plus-static. The error they got was "bash: fork: Invalid argument."
I know that when setting up a foreign architecture chroot, you first download the base system (stage 1) using debootstrap with --foreign, which doesn't require running binaries of the target arch. Then, in stage 2, you run the chroot and use the target's qemu user-static binary to execute commands like /debootstrap/debootstrap --second-stage.
In this case, it worked for armhf but not sparc32plus. The error occurs when trying to fork a process in bash inside the chroot. Forking is a system call that creates a new process, so maybe there's an issue with how the user-mode emulation handles processes.
QEMU has two main modes: user-mode and system-mode. User-mode emulates just the CPU instructions without full hardware virtualization, useful for running binaries of different architectures. System-mode emulates entire systems, including devices and peripherals, which requires higher privileges.
The error here is happening inside the chroot when trying to run bash via QEMU's user-static binary. Since they're using qemu-sparc32plus-static, that's definitely user-mode emulation because system-mode would require more setup like a kernel and disk image.
So the issue seems to be with how QEMU emulates the fork system call in user-mode for sparc32plus. Maybe there's a bug in the implementation of the fork or related syscalls in the user-mode emulator, causing this error when trying to start new processes inside the chroot.
Since it works for armhf but not sparc32plus, it points towards an architecture-specific problem in the user-mode code for sparc32plus. Therefore, this bug is likely related to user-mode emulation.
</think>
user
|