qemu-aarch64-static docker arm64v8/openjdk coredump

[Richard Henwood]

I am using qemu-aarch64-static to run the arm64v8/openjdk official image on my x86 machine. Using QEMU master, I immediately hit a bug which hangs the container. With Ubuntu default version qemu-aarch64 version 2.5.0 (Debian 1:2.5+dfsg-5ubuntu10.24) and qemu-aarch64 version 2.11.1 (v2.11.1-dirty) the hang does not take place.

To reproduce (and get to the core dump):

$ /tmp/tmptgyg3nvh/qemu-aarch64-static/qemu-aarch64-static -version
qemu-aarch64 version 2.11.91 (v2.12.0-rc1-5-g47d3b60-dirty)
Copyright (c) 2003-2017 Fabrice Bellard and the QEMU Project developers

$ docker run -it -v /tmp/tmptgyg3nvh/qemu-aarch64-static:/usr/bin/qemu-aarch64-static arm64v8/openjdk /bin/bash
root@bf75cf45d311:/# javac
Usage: javac <options> <source files>
where possible options include:
  -g Generate all debugging info
<...snip...>
  @<filename> Read options and filenames from file

qemu: uncaught target signal 11 (Segmentation fault) - core dumped
...TERMINAL HANGS...

To get the core dump, In a separate terminal:

# snapshot the file system of the hung image
$ docker commit $(docker ps -aqf "name=latest_qemu") qemu_coredump

# connect with known working qemu
$ docker run -t -v /usr/bin/qemu-aarch64-static:/usr/bin/qemu-aarch64-static -i qemu_coredump /bin/bash

$$ ls -lat
total 10608
<snip>
-rw-r--r-- 1 root root 10792960 Mar 29 18:02 qemu_bash_20180329-180251_1.core
drwxrwxrwt 5 root root 4096 Mar 29 18:02 tmp
<snip>

[Peter Maydell (pmaydell)]

Could you provide a binary that we can use to reproduce, please? (preferably a setup that doesn't require me to figure out how to install and use docker...)

[Peter Maydell (pmaydell)]

I realized I had a javac lying around from last time somebody wanted me to debug a java problem, and I'm also seeing SEGVs with simpler programs like ls (!), so I'll have a look at those and hopefully that will be the same cause as what you're seeing.

[Peter Maydell (pmaydell)]

I think this should be fixed by https://patchwork.ozlabs.org/patch/896295/

(incidentally the segfault is in the guest /bin/sh, not in javac or ls.)

[Peter Maydell (pmaydell)]

Now fixed in master, commit 7f0f4208b3a96, and will be in 2.12.0.

[Richard Henwood (rjhenwood)]

Many thanks!

I've just compiled master, and docker/aarch64/openjdk image now works as expected on my x86 machine.