Re: Upgrade from xen-4.1-testing to xen-unstable report

[Ian Campbell <Ian.Campbell@citrix.com>]

On Thu, 2012-04-12 at 13:50 +0100, Lin Ming wrote:
> On Thu, 2012-04-12 at 07:08 +0000, Ian Campbell wrote:
> > On Wed, 2012-04-11 at 22:23 +0100, Teck Choon Giam wrote:
> > > Hi,
> > > 
> > > This is just my experience about issues I encountered when upgrade
> > > from xen-4.1-testing changeset 23277:80130491806f to xen-unstable
> > > changeset 25191:a95fc7decc83.
> > > 
> > > 1. Immediately after upgrade, xl list show such error:
> > > 
> > > # xl list
> > > libxl: error: libxl.c:506:libxl_list_domain: geting domain info list:
> > > Permission denied
> > > libxl_domain_infolist failed.
> > > 
> > > After a reboot, it is fine.  Any idea why such behaviour?  Imagine if
> > > there are running domUs... this might cause issues to shutdown?  I
> > > will downgrade and repeat such test to confirm.  Might be worth a note
> > > in upgrading note about this if this is intended?
> > 
> > The tools and the hypervisor are a matched pair so you would need to
> > reboot the system in order to use the new tools. This has always been
> > the case with Xen upgrades.
> > 
> > > 2. localtime setting not working.  Set to localtime=1 doesn't seems to
> > > work whereby setting rtc_timeoffset works.  Any idea?
> > 
> > I've CC'd Lin Ming who implemented both of those.
> 
> Just did a quick gdb debug, seems libxl__domain_build_info_setdefault
> was called 3 times. So below statement was executed 3 times too.
> 
> b_info->rtc_timeoffset += tm->tm_gmtoff;

Oh, that sounds like the problem. The setdefault functions are supposed
to be idempotent, IOW calling it two or more times should give the same
result as calling it just once.

I think you need to move this logic from setdefault
    if (libxl_defbool_val(b_info->localtime)) {
        time_t t;
        struct tm *tm;

        t = time(NULL);
        tm = localtime(&t);

        b_info->rtc_timeoffset += tm->tm_gmtoff;
    }

into libxl__build_pre and do that calculation on a temporary variable
whjich you pass to xc_domain_set_time_offset rather than modifying
b_info.

Ian.