Re: [PATCH] Add build time guard to detect off_t mismatch

On Tue, May 12, 2026 at 3:08 PM Jan Kiszka <[email protected]> wrote:
>
> On 12.05.26 15:01, Richard Weinberger wrote:
> > On Thu, May 7, 2026 at 4:22 PM Jan Kiszka <[email protected]> wrote:
> >> OK, given that Xenomai intercepts the mmap path, we could argue that
> >> this is also stable relevant.
> >>
> >> Can you confirm that this issue is truly gone in next, whatever mode you
> >> choose on both sides?
> >
> > Still had no chance to build or run tests with Xenomai next on my ARM boards.
> > But I had a look at the code.
> >
> > I think it's still broken, at least for the following scenario:
> > - 32 bit application built with  _FILE_OFFSET_BITS=64
> > - 32 bit libcobalt without
> > - application calls mmap() using __RT(mmap), so __cobalt_mmap() in libcobalt
> > - off_t differs in size ass seen by caller and callee
>
> A 32-bit app built with _FILE_OFFSET_BITS=64 is supposed to call mmap64
> (as symbol). In you scenario above, it should run into an unresolvable
> symbol error.

Hmm, not here.
I'm building Xenomai with:  CFLAGS="-m32" ./configure && make -j 8 install
Then a program which does __RT(mmap):
$ gcc -o hog hog.c -m32 -D_FILE_OFFSET_BITS=64
$(/usr/xenomai/bin/xeno-config --cflags --skin=posix --ldflags)
$   nm hog|grep mmap
        U __cobalt_mmap

-- 
Thanks,
//richard