Re: [Qemu-devel] Crashes of qemu-system-mips64 and qemu-system-mips64el

[Aurelien Jarno <aurelien@aurel32.net>]

On Sat, Aug 02, 2014 at 10:49:22PM +0200, Torbjörn Granlund wrote:
> Qemu versions 1.7.0, 1.7.1, 2.0.0, 2.1.0 do not run Debian mips64 BE or
> LE stably.  While install in 32-bit mode typically works, running the
> 64-bit kernel causes qemu to segfault or abort after a while.
> 
> How to reproduce:
> 
> Grab installation kernel and initrd:
> 
> ftp://ftp.debian.org/debian/dists/wheezy/main/installer-mips/current/images/malta/netboot/vmlinux-3.2.0-4-4kc-malta
> ftp://ftp.debian.org/debian/dists/wheezy/main/installer-mips/current/images/malta/netboot/initrd.gz
> 
> Start qemu-system-mips64 and perform an installation.  Choose defaults,
> i.e., "Standard system utilities" and "SSH server".
> 
>   qemu-system-mips64 -M malta -m 256 -nographic \
>     -drive file=disk.img,if=virtio,index=0 \
>     -net nic,macaddr=52:54:00:13:06:64 -net user,hostfwd=tcp::20008-:22 \
>     -kernel vmlinux-3.2.0-4-4kc-malta \
>     -initrd initrd.gz \
>     -append "console=ttyS0"
> 
> Copy out /boot somehow.  I usually do "Execute a shell" just before the
> installation is about to finish, and there do
> 
>   mount /dev/vda2 /target
>   mount /dev/vda1 /target/boot
>   mount -t proc proc /target/proc
>   mount --rbind /sys /target/sys
>   mount --rbind /dev /target/dev
>   chroot /target bash
>   /etc/init.d/ssh start
> 
> (assuming "put all files in one partition" was chosen; mount commands
> might need adjustment for other partitioning schemes).
> 
> Then from the host system I do
> 
>   scp -pr -P 20008 localhost:/boot .
> 
> and then quit the shell and finish up the installation.  (Alternatively
> use qemu-nbd or guestfish.)
> 
> Then boot the installed system:
> 
>   qemu-system-mips64 -M malta -cpu 5Kc -m 256 \
>     -drive file=disk.img,if=virtio,index=0 \
>     -net nic,macaddr=52:54:00:13:06:64 -net user,hostfwd=tcp::20008-:22 \
>     -kernel boot/vmlinux-3.2.0-4-5kc-malta \
>     -initrd boot/initrd.img-3.2.0-4-5kc-malta \
>     -append "root=/dev/vda1 console=ttyS0" \
>     -nographic -serial null -monitor null
> 
> Then, log in to the system ("ssh -p 20008 root@localhost) and try the
> system.  It will crash within hours, but usually within minutes.

I have installation running in qemu-system-mips with weeks of uptime
without any problem. I have however tried the above with QEMU 2.1, and
I have been unable to reproduce the issue.

> Safe crash strategy:
> 
>   package_list="gcc g++ gdb make emacs23-nox postfix sharutils zsh rsync ntp"
>   apt-get -y install $package_list gcc-multilib g++-multilib
> 
> Not crashed yet?  Let's provoke it somewhat more:

It didn't crash for me.

>   wget https://ftp.gnu.org/gnu/gmp/gmp-6.0.0a.tar.bz2
>   tar xf gmp-6.0.0a.tar.bz2
>   cd gmp-6.0.0
>   (configure && make && while true; do make check; done) >&/dev/null
> 
> Note that I have reproduced this problem on several host machines.  Host
> system stability is not the root cause.  The host system has been either
> GNU/Linux or FreeBSD.  I have not found a stable setup since before qemu
> 1.7.0.  I know it was stable around 1.5.x or 1.6.x.  (Even older qemus
> executed a few instructions incorrectly, making them inadequate for my
> use.)
> 

It's now running for more than 48 hours, and hasn't crashed yet.

Could you give us more details about your host, especially if it is a
32-bit or a 64-bit one? Also a cat /proc/cpuinfo would be useful as some
instructions are enabled or not depending on the host support.

-- 
Aurelien Jarno                          GPG: 4096R/1DDD8C9B
aurelien@aurel32.net                 http://www.aurel32.net