From: Benjamin Herrenschmidt <benh@au1.ibm.com>
To: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
Andy Lutomirski <luto@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
"H. Peter Anvin" <hpa@zytor.com>
Cc: linux-kernel@vger.kernel.org, linux-api@vger.kernel.org,
"Paul E . McKenney" <paulmck@linux.vnet.ibm.com>,
Boqun Feng <boqun.feng@gmail.com>, Andrew Hunter <ahh@google.com>,
Maged Michael <maged.michael@gmail.com>,
Avi Kivity <avi@scylladb.com>, Paul Mackerras <paulus@samba.org>,
Michael Ellerman <mpe@ellerman.id.au>,
Dave Watson <davejwatson@fb.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>,
Andrea Parri <parri.andrea@gmail.com>,
Russell King <linux@armlinux.org.uk>,
Greg Hackmann <ghackmann@google.com>,
Will Deacon <will.deacon@arm.com>, David Sehr <sehr@google.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
x86@kernel.org, linux-arch@vger.kernel.org, stable@kernel.org
Subject: Re: [RFC PATCH v2] Fix: x86: Add missing core serializing instruction on migration
Date: Mon, 13 Nov 2017 10:51:47 +1100 [thread overview]
Message-ID: <1510530707.12797.42.camel@au1.ibm.com> (raw)
In-Reply-To: <1510529164.12797.41.camel@kernel.crashing.org>
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.
prev parent reply other threads:[~2017-11-12 23:52 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-11-11 15:03 Mathieu Desnoyers
2017-11-11 15:14 ` Mathieu Desnoyers
2017-11-12 23:26 ` Benjamin Herrenschmidt
2017-11-12 23:51 ` Benjamin Herrenschmidt [this message]
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