Re: [PATCH v2 4/4] x86/static_call: Add inline static call implementation for x86-64

[Jiri Kosina]

On Thu, 29 Nov 2018, Peter Zijlstra wrote:

> > int3 isnât IST anymore, so the int3 instruction conditionally 
> > subtracts 8 from RSP and then pushes SS, etc. So my email was 
> > obviously wrong wrt âcsâ, but youâre still potentially overwriting the 
> > int3 IRET frame.
> 
> ARGH!..
> 
> can't we 'fix' that again? The alternative is moving that IRET-frame and
> fixing everything up, which is going to be fragile, ugly and such
> things more.
> 
> Commit d8ba61ba58c8 ("x86/entry/64: Don't use IST entry for #BP stack")
> doesn't list any strong reasons for why it should NOT be an IST.

It's CVE-2018-8897.

-- 
Jiri Kosina
SUSE Labs