From: Benjamin Herrenschmidt <benh-8fk3Idey6ehBDgjK7y7TUQ@public.gmane.org>
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>
Cc: linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
"Paul E . McKenney"
<paulmck-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>,
Boqun Feng <boqun.feng-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
Andrew Hunter <ahh-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>,
Maged Michael
<maged.michael-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
Avi Kivity <avi-VrcmuVmyx1hWk0Htik3J/w@public.gmane.org>,
Paul Mackerras <paulus-eUNUBHrolfbYtjvyW6yDsg@public.gmane.org>,
Michael Ellerman <mpe-Gsx/Oe8HsFggBc27wqDAHg@public.gmane.org>,
Dave Watson <davejwatson-b10kYP2dOMg@public.gmane.org>,
Thomas Gleixner <tglx-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org>,
Ingo Molnar <mingo-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>,
Andrea Parri
<parri.andrea-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
Russell King <linux-I+IVW8TIWO2tmTQ+vhA3Yw@public.gmane.org>,
Greg Hackmann <ghackmann-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>,
Will Deacon <will.deacon-5wv7dgnIgG8@public.gmane.org>,
David Sehr <sehr-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>,
Linus Torvalds
<torvalds-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>,
x86-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org,
linux-arch-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
stable-DgEjT+Ai2ygdnm+yROfE0A@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 [thread overview]
Message-ID: <1510530707.12797.42.camel@au1.ibm.com> (raw)
In-Reply-To: <1510529164.12797.41.camel-XVmvHMARGAS8U2dJNN8I7kB+6BGkLq7r@public.gmane.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.
WARNING: multiple messages have this Message-ID (diff)
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)
Message-ID: <20171112235147.1ae-9od_oApXsCEG-30WmES_rnlel9qLchQTO4laNno@z> (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.
next prev parent reply other threads:[~2017-11-12 23:51 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-11-11 15:03 [RFC PATCH v2] Fix: x86: Add missing core serializing instruction on migration Mathieu Desnoyers
2017-11-11 15:03 ` Mathieu Desnoyers
2017-11-11 15:14 ` Mathieu Desnoyers
2017-11-11 15:14 ` Mathieu Desnoyers
2017-11-12 23:26 ` Benjamin Herrenschmidt
[not found] ` <1510529164.12797.41.camel-XVmvHMARGAS8U2dJNN8I7kB+6BGkLq7r@public.gmane.org>
2017-11-12 23:51 ` Benjamin Herrenschmidt [this message]
2017-11-12 23:51 ` Benjamin Herrenschmidt
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