Re: [Qemu-devel] FW: qemu-ppc core dumps randomly on postgresql thread safety test

[Peter Maydell]

On 6 January 2012 12:37, Rengert, Mark <address@hidden> wrote:
> I am using scratchbox2 under Ubuntu 10.04 to build postgresql for ppc. About 
> half the time
> the configuration test for thread safety fails with a qemu-ppc coredump. It 
> fails less often
> when QEMU_STRACE is defined but it still fails sometimes. It appears to 
> happen in the
> pthread_join() call, I think.
>
> Here is the info requested on the KVM bug report webpage 
> (http://www.linux-kvm.org/page/Bugs):
>
> CPU model: Intel(R) Core(TM) i5-2400 CPU @ 3.10GHz
>
> Host kernel: Linux florida 2.6.32-36-generic-pae #79-Ubuntu SMP Tue Nov 8 
> 23:25:26 UTC 2011 i686 GNU/Linux
>
> Guest: via "sb2 -t powerpc-unknown-linux-gnu"
>
> Qemu command: (generated by scratchbox) "/usr/bin/qemu-ppc -U LD_PRELOAD -L / 
> -0 ./conftest ./conftest"

> Scratchbox2 version: 2.0-lta101
> Qemu version: qemu-ppc version 0.12.3 (qemu-kvm-0.12.3), Copyright (c) 
> 2003-2008 Fabrice Bellard
> Ubuntu package: qemu-kvm-extras 0.12.3+noroms-0ubuntu9.16 (latest version 
> available for Ubuntu 10.04)

Two things:
(1) this is a known bug, qemu has some race conditions which are
exposed by running
heavily multithreaded code in user-mode, and which can cause crashes/hangs/other
problems.
(2) 0.12.3 is a really old version. As it happens I know we haven't
fixed this bug yet,
but in most other cases we'd just ask you to retry with a newer QEMU version.

-- PMM