From: Will Deacon <will.deacon@arm.com>
To: Jon Masters <jcm@redhat.com>
Cc: peterz@infradead.org, paulmck@linux.vnet.ibm.com,
kirill.shutemov@linux.intel.com, linux-kernel@vger.kernel.org,
ynorov@caviumnetworks.com, rruigrok@codeaurora.org,
linux-arch@vger.kernel.org, akpm@linux-foundation.org,
catalin.marinas@arm.com, timur@codeaurora.org
Subject: Re: [RFC PATCH 0/2] Missing READ_ONCE in core and arch-specific pgtable code leading to crashes
Date: Thu, 5 Oct 2017 17:54:33 +0100 [thread overview]
Message-ID: <20171005165433.GA4047@arm.com> (raw)
In-Reply-To: <95366fe6-e1eb-dd39-6f13-903704b5180f@redhat.com>
On Tue, Oct 03, 2017 at 02:36:42AM -0400, Jon Masters wrote:
> On 09/29/2017 04:56 AM, Will Deacon wrote:
>
> > The full fix isn't just cosmetic; it's also addressing the wider problem
> > of unannotated racing page table accesses outside of the specific failure
> > case we've run into.
>
> Let us know if there are additional tests we should be running on the
> Red Hat end. We've got high hundreds of ARM server systems at this
> point, including pretty much everything out there.
TBH, there's nothing ARM-specific about this issue afaict and it should
be reproducible on x86 if the compiler can keep the initially loaded pmd
live in a GPR for long enough.
As for wider problems, you want to stress anything that does page table
modification concurrently with lockless walkers (although GUP looks mostly
ok modulo the lack of pud_trans_huge support, which I'll try to fix if
I find time).
Will
prev parent reply other threads:[~2017-10-05 16:54 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-09-27 15:49 [RFC PATCH 0/2] Missing READ_ONCE in core and arch-specific pgtable code leading to crashes Will Deacon
2017-09-27 15:49 ` [RFC PATCH 1/2] arm64: mm: Use READ_ONCE/WRITE_ONCE when accessing page tables Will Deacon
2017-09-28 8:38 ` Peter Zijlstra
2017-09-28 8:45 ` Will Deacon
2017-09-28 15:43 ` Paul E. McKenney
2017-09-28 15:49 ` Will Deacon
2017-09-28 16:07 ` Paul E. McKenney
2017-09-28 18:59 ` Michael Cree
2017-09-29 0:58 ` Paul E. McKenney
2017-09-29 9:08 ` Will Deacon
2017-09-29 16:29 ` Paul E. McKenney
2017-09-29 16:33 ` Will Deacon
2017-10-03 19:11 ` Paul E. McKenney
2017-10-05 16:31 ` Will Deacon
2017-10-05 19:22 ` Paul E. McKenney
2017-10-05 19:31 ` Andrea Parri
2017-10-05 20:09 ` Paul E. McKenney
2017-09-28 19:18 ` Timur Tabi
2017-09-27 15:49 ` [RFC PATCH 2/2] mm: page_vma_mapped: Ensure pmd is loaded with READ_ONCE outside of lock Will Deacon
2017-09-27 22:01 ` [RFC PATCH 0/2] Missing READ_ONCE in core and arch-specific pgtable code leading to crashes Yury Norov
2017-09-28 17:30 ` Richard Ruigrok
2017-09-28 19:38 ` Jon Masters
2017-09-29 8:56 ` Will Deacon
2017-10-03 6:36 ` Jon Masters
2017-10-05 16:54 ` Will Deacon [this message]
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