Re: [PATCH] Prevent trace call into unloaded module text

[Wu Fengguang <fengguang.wu@intel.com>]

On Wed, Nov 26, 2008 at 01:17:55PM +0200, Avi Kivity wrote:
> Wu Fengguang wrote:
> > Add marker_synchronize_unregister() before module unloading.
> > This prevents possible trace calls into unloaded module text.
> >
> > Signed-off-by: Wu Fengguang <wfg@linux.intel.com>
> > ---
> > diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
> > index a87f45e..64f38b3 100644
> > --- a/virt/kvm/kvm_main.c
> > +++ b/virt/kvm/kvm_main.c
> > @@ -2102,5 +2102,6 @@ void kvm_exit(void)
> >  	kvm_arch_exit();
> >  	kvm_exit_debug();
> >  	__free_page(bad_page);
> > +	marker_synchronize_unregister();
> >  }
> >  EXPORT_SYMBOL_GPL(kvm_exit);
> >   
> 
> What about kvm-intel.ko and kvm-amd.ko?  They also contain markers.

vmx_exit and svm_exit() all calls into kvm_exit(), so they have been
handled in a common way.

> (and, why doesn't module unload do this automatically?)

Maybe most modules don't need it for now?

Thanks,
Fengguang