Re: [BUG] XEN 4.3.3 - segfault in xl create for HVM with PCI passthrough

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

On Mon, 2014-12-01 at 11:34 +0800, Dennis Lan (dlan) wrote:
> On Mon, Nov 10, 2014 at 8:09 PM, Ian Campbell <Ian.Campbell@citrix.com> wrote:
> > On Mon, 2014-11-10 at 12:44 +0100, Atom2 wrote:
> >
> >> > I'm afraid it's looking more and more like a toolchain issue. I'm not
> >> > expert on this side on things but it looks to me like you are hitting an
> >> > issue with some sort of buffer overflow check gone wrong? I think you'll
> >> > need a gcc hardening person for this one.
> >> The issue currently is with the guys at gentoo (for links please again
> >> see my latest post to the list from Sunday which also seems to confirm
> >> that the issue is not confined to 4.3.3 but also 4.4.1).
> >
> > OK, I'll wait and see what the gentoo folks have to say before looking
> > any close then, thanks.
> >
> Hi Ian
>  what we found now is, the Gentoo's hardened toolchain, turn CFLAGS
> -fstack-check on by default, with this flag and compile gcc will
> result xl segfault (actually with libgcc_s.so)
>  we have a patch to force gcc build libgcc(only this part) code with
> -fstack-check=no, make the segfault gone
>  more info can be found at https://bugs.gentoo.org/show_bug.cgi?id=528690

Excellent, thanks for letting us know.

Just to be sure: This isn't (so far as anyone knows) the result of any
coding/build-system problem in Xen, right?

Ian.