Re: Compliling Xen 4.5.0 Fails with error: ‘bufioreq_pfn’ may be used uninitialised in this function [-Werror=uninitialized]

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

On Mon, 2015-03-16 at 09:45 +0000, Paul Durrant wrote:
> Those line numbers don't work for me. I did a checkout of
> RELEASE-4.5.0 and, whilst bufioreq_pfn is indeed declared on line 718,
> I see no reference to it on line 487. Also, if I compile debug=n I see
> no problem. Is it possible you don't have a clean checkout of 4.5.0?
> What version of gcc are you using?

Doing
 git show RELEASE-4.5.0:xen/arch/x86/hvm/hvm.c  > x
gets me a file x where line 487 is the first line (defn of "i") of:

static void hvm_free_ioreq_gmfn(struct domain *d, unsigned long gmfn)
{
    unsigned int i = gmfn - d->arch.hvm_domain.ioreq_gmfn.base;

    clear_bit(i, &d->arch.hvm_domain.ioreq_gmfn.mask);
}

My guess was that it was the call from the fial3 label in
hvm_ioreq_server_map_pages(). I can see how gcc wouldn't always be able
to reason about it always being initialised.

Ian.