Re: [PATCH] avoid race condition in pick_next_task_fair inkernel/sched_fair.c

From: Miklos Vajna
Date: Wed Dec 22 2010 - 08:32:10 EST


On Wed, Dec 22, 2010 at 10:07:22AM +0100, Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:
> On Wed, 2010-12-22 at 09:41 +0100, Mike Galbraith wrote:
> > On Wed, 2010-12-22 at 09:29 +0100, Peter Zijlstra wrote:
> > > On Wed, 2010-12-22 at 01:22 +0100, Miklos Vajna wrote:
> > > > Please let me know if you need more info.
> > >
> > > What distro are you using? it looks like systemd is involved and I'm
> > > actively avoiding anything using that crap.

First, sorry about the systemd list, I did not know it's
subscriber-only.

This is Frugalware Linux, and it's disabled by default here as well.

> > Heh, gearing up to hunt a bug it triggers, just doing all I had to do to
> > get the thing built and installed blew my box _all up_. I still have
> > smoldering bits lying about a week later.
>
> There's a reason I was asking for a qemu image ;-), I'm not letting that
> stuff anywhere near my regular machines.

Sure - here is a qcow image (871M):

http://frugalware.org/~vmiklos/files/systemd.img

Here is how I started it:

qemu-kvm -vnc :0 -m 1G -hda systemd.img

$ qemu-kvm -version
QEMU PC emulator version 0.12.3 (qemu-kvm-0.12.3), Copyright (c) 2003-2008 Fabrice Bellard

There are two menu entries in grub config - first is sysvinit, that
boots up correctly here, you can login using root / root. The second is
systemd, that just panics here almost all the time. In case it would
not, use 'systemctl emergency' as root and that will trigger the bug. :)

If you need more packages in the virtual machine and the pacman package
manager sounds exotic, here is a quick help:

http://frugalware.org/docs/pacman-g2#_apt_pacman_g2_cross_reference

Thanks,

Miklos

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