Re: [RESEND] Spectre-v2 (IBPB/IBRS) and SSBD fixes for 4.4.y

From: Greg KH <gregkh@linuxfoundation.org>
To: "Srivatsa S. Bhat" <srivatsa@csail.mit.edu>
Cc: "Dave Hansen" <dave@sr71.net>,
	catalin.marinas@arm.com, "Wanpeng Li" <kernellwp@gmail.com>,
	"Andi Kleen" <ak@linux.intel.com>,
	linux-tip-commits@vger.kernel.org,
	"Piotr Luc" <piotr.luc@intel.com>, "Mel Gorman" <mgorman@suse.de>,
	"Van De Ven, Arjan" <arjan.van.de.ven@intel.com>,
	xen-devel <xen-devel@lists.xenproject.org>,
	"Alexander Sergeyev" <sergeev917@gmail.com>,
	"Brian Gerst" <brgerst@gmail.com>,
	"Andy Lutomirski" <luto@kernel.org>,
	MickaëlSalaün <mic@digikod.net>,
	"Thomas Gleixner" <tglx@linutronix.de>,
	"Joe Konno" <joe.konno@linux.intel.com>,
	"Laura Abbott" <labbott@fedoraproject.org>,
	"Will Drewry" <wad@chromium.org>,
	LKML <linux-kernel@vger.kernel.org>,
	"Jia Zhang" <qianyue.zj@alibaba-inc.com>,
	"Andrew Morton" <akpm@linux-foundation.org>,
	"Linus Torvalds" <torvalds@linux-foundation.org>,
	"David Woodhouse" <dwmw@amazon.co.uk>,
	srinidhir@vmware.com
Subject: Re: [RESEND] Spectre-v2 (IBPB/IBRS) and SSBD fixes for 4.4.y
Date: Tue, 7 Aug 2018 15:49:34 +0200	[thread overview]
Message-ID: <20180807134934.GA16837@kroah.com> (raw)
In-Reply-To: <8a87a705-97c0-eb3d-8878-8ffe052f065d@csail.mit.edu>

On Fri, Aug 03, 2018 at 04:20:31PM -0700, Srivatsa S. Bhat wrote:
> On 8/2/18 3:22 PM, Kees Cook wrote:
> > On Thu, Aug 2, 2018 at 12:22 PM, Srivatsa S. Bhat
> > <srivatsa@csail.mit.edu> wrote:
> >> On 7/26/18 4:09 PM, Kees Cook wrote:
> >>> On Tue, Jul 24, 2018 at 3:02 PM, Jiri Kosina <jikos@kernel.org> wrote:
> >>>> On Tue, 24 Jul 2018, Srivatsa S. Bhat wrote:
> >>>>
> >>>>> However, if you are proposing that you'd like to contribute the enhanced
> >>>>> PTI/Spectre (upstream) patches from the SLES 4.4 tree to 4.4 stable, and
> >>>>> have them merged instead of this patch series, then I would certainly
> >>>>> welcome it!
> >>>>
> >>>> I'd in principle love us to push everything back to 4.4, but there are a
> >>>> few reasons (*) why that's not happening shortly.
> >>>>
> >>>> Anyway, to point out explicitly what's really needed for those folks
> >>>> running 4.4-stable and relying on PTI providing The Real Thing(TM), it's
> >>>> either a 4.4-stable port of
> >>>>
> >>>>         http://kernel.suse.com/cgit/kernel-source/plain/patches.suse/x86-entry-64-use-a-per-cpu-trampoline-stack.patch?id=3428a77b02b1ba03e45d8fc352ec350429f57fc7
> >>>>
> >>>> or making THREADINFO_GFP imply __GFP_ZERO.
> >>>
> >>> This is true in Linus's tree now. Should be trivial to backport:
> >>> https://git.kernel.org/linus/e01e80634ecdd
> >>>
> >>
> >> Hi Jiri, Kees,
> >>
> >> Thank you for suggesting the patch! I have attached the (locally
> >> tested) 4.4 and 4.9 backports of that patch with this mail. (The
> >> mainline commit applies cleanly on 4.14).
> >>
> >> Greg, could you please consider including them in stable 4.4, 4.9
> >> and 4.14?
> > 
> > I don't think your v4.9 is sufficient: it leaves the vmapped stack
> > uncleared. v4.9 needs ca182551857 ("kmemleak: clear stale pointers
> > from task stacks") included in the backport (really, just adding the
> > memset()).
> > 
> 
> Ah, I see, thank you! I have attached the updated patchset for 4.9
> with this mail.
> 
> > Otherwise, yup, looks good.
> > 
> Thank you for reviewing the patches!
>  
> Regards,
> Srivatsa
> VMware Photon OS

These work for 4.9, do you also have a set for 4.4?

thanks,

greg k-h

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