On Tue, May 26, 2026, 5:59 PM H.J. Lu <[email protected]> wrote:

> On Wed, May 27, 2026 at 8:39 AM Andrew Pinski
> <[email protected]> wrote:
> >
> > On Tue, May 26, 2026 at 3:56 PM H.J. Lu <[email protected]> wrote:
> > >
> > > On Wed, May 27, 2026 at 6:41 AM Iain Sandoe <[email protected]>
> wrote:
> > > >
> > > >
> > > >
> > > > > On 26 May 2026, at 22:35, H.J. Lu <[email protected]> wrote:
> > > > >
> > > > > On Tue, May 26, 2026 at 11:19 PM Iain Sandoe <
> [email protected]> wrote:
> > > > >>
> > > > >> HJ,
> > > > >>
> > > > >> Bootstrap on 32b Darwin (and 64b Darwin with 32b multilib) is
> still broken after
> > > > >> more than three weeks,
> > > > >>
> > > > >> It is reasonable to have a temporary break if there is a trivial
> typo or other fix
> > > > >> that can be applied in a timely manner.
> > > > >>
> > > > >> However, in this case, it seems your initial design needed some
> amendment,
> > > > >> and that means a more complex fix is needed - which needs
> additional review.
> > > > >>
> > > > >> Today I now faced two concurrent bootstrap breaks on some
> platform versions
> > > > >> - this is just consuming time in a non-constructive manner.
> > > > >
> > > > > It only shows that maintainers pay no attention to Darwin.  In the
> meantime,
> > > > > you can submit a very simple libssp patch to fix Darwin build by
> changing
> > > > > __stack_chk_guard to unsigned long for Darwin.
> > > >
> > > > I find this unbelievable, and cannot think of any other maintainer
> who would
> > > > leave a regulalry-tested platform broken for weeks, and then try
> pass the blame
> > > > to reviewers for not being quick enough review band aid upon band
> aid.
> > > >
> > > > The responsibility for producing good reviewed patches lies with you
> - not
> > > > with other maintainers for platforms you break with bad patches, and
> not with
> > > > reviewers who might have more pressing things to address.
> > >
> > > I submitted a fix and suggested one line change to address Darwin
> build.
> > > You choose to ignore my suggestion.
> > >
> > > > I would be very disappointed if this is what is considered to be
> “good community” behaviour.
> > > >
> > > > Iain
> > > > ** even with all your patches applied the testcases need work - it
> is not at all
> > > > helpful that you leave it to others to finish off your incomplete
> work.
> > > >
> > >
> > > I submitted patches to address regressions.   Some newly added tests
> failed
> > > due to the existing libssp implementation bug.   You can xfail them if
> ssp isn't
> > > provided in libc.
> >
> > So I am going to step into this mess and explain how this mess came
> > about in the first place.
> >
> > Here is the situation and the problem is stack_protect_guard looks
> > like a mess to begin with.
> > GCC documented it this way: `The type of this variable must be
> > @code{ptr_type_node}.`
> > So libssp followed this. BUT glibc, and many other libc's didn't
> > follow this document part. glibc (and many other libcs and linux
> > kernel even) used `uintptr_t`. And GCC didn't check the type
> > beforehand.
> >
> > And then HJL changed it to be a type which is the same size and
> > signedness as `uintptr_t` BUT not exactly the same (on some targets)
> > and also checking the type at this stage.
> > HJL didn't update libssp originally. So that broke some x86 targets
> > including darwin. And then when he changed libssp it still was broken
> > for i?86-darwin (32bit) because in that case the difference between
> > `unsigned long` and `unsigned int` which are not compatible at all.
> > (note systemd also needed a change too).
> >
> > So we are now in limbo right now where i?86-darwin is broken (and
> > x86_64-darwin because of multilib).
> >
> > I think we should revert the original patch which checked the type and
> > all other band-aids. And start over with a different fix for the
> > original issue here.
>
> This mess has been there for a very long time.  My patch just exposes
> it.   Requires ssp in libc should resolve most issues.
>

Yes our policy on reverting makes a mention of that issue:
Note that no distinction is made between patches which are themselves buggy
and patches that expose latent bugs elsewhere in the compiler.





> > Note our current policy: https://gcc.gnu.org/develop.html#reversion
> > seems not to take into account this kind of situation. Because even
> > though there is a "fix", we don't know how many other sources will be
> > broken or other libc will have to change due to this change. And the
> > patch to "fix" the issue seems like it is not being reviewed either. I
> > can't speak for others but I am not comfortable reviewing it.
> >
> > Plus what was documented on the type before is now different from what
> > is being checked. Even though it does not seem like it will cause an
> > ABI incompatibility; it could still end up being an ABI issue.
> >
> > Thanks,
> > Andrea
> >
> >
> > >
> > >
> > > --
> > > H.J.
>
>
>
> --
> H.J.
>

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