Re: [PATCH 1/4] signals/sigaltstack: If SS_AUTODISARM, bypass on_sig_stack

[Andy Lutomirski]

On May 3, 2016 11:32 PM, "Ingo Molnar" <mingo@xxxxxxxxxx> wrote:
>
>
> * Andy Lutomirski <luto@xxxxxxxxxx> wrote:
>
> > If a signal stack is set up with SS_AUTODISARM, then the kernel
> > inherently avoids incorrectly resetting the signal stack if signals
> > recurse: the signal stack will be reset on the first signal
> > delivery.  This means that we don't need check the stack pointer
> > when delivering signals if SS_AUTODISARM is set.
> >
> > This will make segmented x86 programs more robust: currently there's
> > a hole that could be triggered if ESP/RSP appears to point to the
> > signal stack but actually doesn't due to a nonzero SS base.
> >
> > Signed-off-by: Stas Sergeev <stsp@xxxxxxx>
>
> Presuably that SOB from Stas is stray, as there's no matching From: line?
> I've removed it.

Yes.  It was a cut-and-paste-o -- I meant to change it to cc.

>
> Thanks,
>
>         Ingo