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

On May 3, 2016 11:32 PM, "Ingo Molnar" [off-list ref] wrote:

* Andy Lutomirski [off-list ref] wrote:

quoted

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 <redacted>

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