id = 1812
title = "older programs running under qemu-aarch64 segfaults"
state = "closed"
created_at = "2023-08-05T16:07:48.879Z"
closed_at = "2023-08-11T06:02:34.362Z"
labels = ["Closed::Fixed", "accel: TCG", "linux-user", "target: arm"]
url = "https://gitlab.com/qemu-project/qemu/-/issues/1812"
host-os = "Linux"
host-arch = "amd64"
qemu-version = "8.1.0-rc2"
guest-os = "Debian Jessie, Ubuntu Xenial, ..."
guest-arch = "aarch64"
description = """Numerous aarch64 programs segfaults when run under qemu-aarch64."""
reproduce = """1. Install an arm64 chroot (with working qemu-aarch64 binfmt_misc setup):
```
debootstrap --variant=minbase --arch=arm64 jessie /tmp/jessie-arm64/ http://archive.debian.org/debian
or
debootstrap --variant=minbase --arch=arm64 xenial /tmp/xenial-arm64/ http://ports.ubuntu.com/
```
2. build qemu-aarch64; cp qemu-aarch64 /tmp/jessie-arm64/
3. chroot /tmp/jessie-arm64/
4. ./qemu-aarch64 /bin/ls
```
qemu: uncaught target signal 11 (Segmentation fault) - core dumped
Segmentation fault 
```"""
additional = """Old userspace (eg Debian jessie, Ubuntu xenial) does not work within qemu 8.1-rc2 aarch64 linux-user emulation, since commit 59b6b42cd3446862567637f3a7ab31d69c9bef51 .  My guess is that old userspace isn't prepared for recent CPU features, but it still smells strange.

Not all programs segfaults. dash works, ls or bash does not.

A chroot is easier in this case, since many old programs don't run inside current environment, like asserting while reading locale-specific information.  To run debootstrap and to enter the resulting chroot, a working qemu-aarch64 binfmt_misc setup is needed.

Reverting the mentioned commit makes everything work again."""