From mboxrd@z Thu Jan  1 00:00:00 1970
From: Benjamin Herrenschmidt <benh-8fk3Idey6ehBDgjK7y7TUQ@public.gmane.org>
Subject: Re: [RFC PATCH v2] Fix: x86: Add missing core serializing
 instruction on migration
Date: Mon, 13 Nov 2017 10:51:47 +1100
Message-ID: <1510530707.12797.42.camel@au1.ibm.com>
References: <20171111150357.26072-1-mathieu.desnoyers@efficios.com>
         <1510529164.12797.41.camel@kernel.crashing.org>
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To: Mathieu Desnoyers <mathieu.desnoyers-vg+e7yoeK/dWk0Htik3J/w@public.gmane.org>, Andy Lutomirski <luto-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>, Peter Zijlstra <peterz-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org>, "H. Peter Anvin" <hpa-YMNOUZJC4hwAvxtiuMwx3w@public.gmane.org>
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On Mon, 2017-11-13 at 10:26 +1100, Benjamin Herrenschmidt wrote:
> On Sat, 2017-11-11 at 10:03 -0500, Mathieu Desnoyers wrote:
> > x86 has a missing core serializing instruction in migration scenarios.
> > 
> > Given that x86-32 can return to user-space with sysexit, and x86-64
> > through sysretq and sysretl, which are not core serializing, the
> > following user-space self-modifiying code (JIT) scenario can occur:
> 
> Is this about load/store consistency ? In this case, don't you also
> have problems with get/put_user and not just going to userspace ?

Ah forget it, I saw Linus earlier messages.

Cheers,
Ben.