2017-11-12 23:54:13

by Benjamin Herrenschmidt

[permalink] [raw]
Subject: Re: [RFC PATCH v2] Fix: x86: Add missing core serializing instruction on migration

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.


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