[Fedora-xen] 4gb seg fixup, process on FC6 domU

[Daniel P. Berrange]

On Wed, Dec 20, 2006 at 07:58:46PM +0500, Asrai khn wrote:
> On 12/20/06, Daniel P. Berrange <berrange at redhat.com> wrote:
> >
> >On Wed, Dec 20, 2006 at 07:37:41PM +0500, Asrai khn wrote:
> >> On 12/20/06, Daniel P. Berrange <berrange at redhat.com> wrote:
> >> >On Wed, Dec 20, 2006 at 07:19:06PM +0500, Asrai khn wrote:
> >> >
> >> >If you're not using pygrub, then you'll at least need to make sure the
> >> >correct 'kernelcap' file is installed in the guest, with file name
> >> >matching the kernel version.
> >>
> >>
> >> What do you mean by install 'kernelcap' file on guest?
> >> you want me to create this file manually in the specific path and then
> >echo
> >> 'something' to it?
> >
> >Actually i've realized its not the name of the config name which matters.
> >The issue is you need to run 'ldconfig' after creating the config file so
> >that it updates its library cache
> >
> >  echo "hwcap 0 nosegneg" > /etc/ld.conf.so.d/nosegneg.conf
> >  ldconfig
> 
> 
> Right, I did this and run 'ldconfig' afterward but  its
> /etc/ld.so.conf.d/nosegneg.conf not /etc/ld.conf.so.d/nosegneg.conf , may be
> typo
> 
> Once you've done that, you can verify the linker knows about Xen variant
> >by looking for libc mapping. eg before I add the hwcap stuff it shows:
> >
> >  # ldconfig -v -p 2>&1 | grep libc.so
> >        libc.so.6 (libc6, OS ABI: Linux 2.6.9) => /lib/libc.so.6
> 
> 
> I get this before echo thing...
> 
> ldconfig -v -p 2>&1 | grep libc.so
>        libc.so.6 (libc6, OS ABI: Linux 2.6.9) => /lib/libc.so.6
> 
> 
> Once I create the hwcap setting & re-run ldconfig it shows
> >
> >  # ldconfig -v -p 2>&1 | grep libc.so
> >        libc.so.6 (libc6, hwcap: 0x0018000000000000, OS ABI: Linux 2.6.9)
> >=> /lib/i686/nosegneg/libc.so.6
> >        libc.so.6 (libc6, OS ABI: Linux 2.6.9) => /lib/libc.so.6
> 
> 
> After hwcap I get ..
> 
> ldconfig -v -p 2>&1 | grep libc.so
>        libc.so.6 (libc6, hwcap: 0x0018000000000000, OS ABI: Linux 2.6.9) =>
> /lib/i686/nosegneg/libc.so.6
>        libc.so.6 (libc6, OS ABI: Linux 2.6.9) => /lib/libc.so.6
> 
> But still getting those  '4gb seg fixup, process' errors
> 
> ldconfig is enough not need to reboot the guest right?

Nope. All you've done is update the linker cache. This means any new processes
you've spawned will use the correct libc.  Any old processes will still have
the old (Xen unfriendly)  libc mapped into memory. A reboot is the only way
to get everything using the new settings I'm afraid.



NB, even with this change you'll see the 4gb fixup messages if you run any
mono processes - eg beagle or tomboy - this is a bug in the Mono VM for
which there isn't any fix yet.

Regards,
Dan.
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