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    SubjectRe: sigaltstack breaks swapcontext()
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    07.01.2016 20:23, Andy Lutomirski пишет:
    > On Thu, Jan 7, 2016 at 7:33 AM, Stas Sergeev <stsp@list.ru> wrote:
    >> 06.01.2016 22:53, Andy Lutomirski пишет:
    >>> On Wed, Jan 6, 2016 at 11:31 AM, Stas Sergeev <stsp@list.ru> wrote:
    >>>> Exactly.
    >>>> Do you think this can be ignored?
    >>>> A man page should then be corrected with EPERM and the
    >>>> above note removed, right?
    >>>>
    >>> I think it can be ignored. I'd go the SS_FORCE route, though, to
    >>> maintain POSIX compliance.
    >> I think such a flag would be a wrong thing to do.
    >> Allowing only SS_DISABLE (without any new flags) keeps
    >> you still "compatible with posix", and anything beyond
    >> SS_DISABLE in a sighandler is not needed.
    >>
    >> So I think we only have the following options:
    >> 1. Remove the check and forget (if anything, glibc can
    >> add the EPERM check to stay compatible with crap).
    >> 2. Allow only SS_DISABLE. This will mean a large patch,
    >> touching all arches, but the bonus is the compatibility
    >> with posix, that no one needs in this particular case.
    > Why does allowing SS_DISABLE require touching all arches?
    I mean, if we also consistently return SA_ONSTACK even
    after SS_DISABLE. This will require kernel to save the
    ss_flags separately, and not to use "if (ss_size)" checks.
    Of course if we don't want to return SA_ONSTACK, we
    should just remove EPERM as I don't think it serves any
    other purpose than that.

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