Re: [PATCH 1/2] sigaltstack: support SS_AUTODISARM for CONFIG_COMPAT

[Andy Lutomirski]

On Sun, Feb 5, 2017 at 2:12 AM, Stas Sergeev <stsp@xxxxxxx> wrote:
> Currently SS_AUTODISARM is not supported in compatibility
> mode, but does not return -EINVAL either. This makes dosemu
> built with -m32 on x86_64 to crash. Also the kernel's sigaltstack
> selftest fails if compiled with -m32.
>
> This patch adds the needed support.
>
> Suggesting for -stable.

This looks correct.  I find it odd that we used to check the old sp to
figure out whether to put SA_ONSTACK into the signal frame, but I do
think the new behavior is better.  In any event, this changes the
compat case to work like the native case, and no one noticed when the
native behavior changed, so it's fine by me.

--Andy