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From: Suren Baghdasaryan <surenb@google.com>
Date: Thu, 25 Jan 2024 18:19:19 -0800
Message-ID: <CAJuCfpGy=AmngLNMG737N4W_RXz=pRfisa1o7j9chBQ7=Mq6Kw@mail.gmail.com>
Subject: Re: [PATCH 1/1] arch/arm/mm: fix major fault accounting when retrying
 under per-VMA lock
To: Andrew Morton <akpm@linux-foundation.org>
Cc: willy@infradead.org, will@kernel.org, catalin.marinas@arm.com, 
	palmer@dabbelt.com, mpe@ellerman.id.au, christophe.leroy@csgroup.eu, 
	agordeev@linux.ibm.com, gerald.schaefer@linux.ibm.com, 
	dave.hansen@linux.intel.com, luto@kernel.org, peterz@infradead.org, 
	x86@kernel.org, linux-arm-kernel@lists.infradead.org, 
	linuxppc-dev@lists.ozlabs.org, linux-riscv@lists.infradead.org, 
	linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org, 
	Russell King <rmk+kernel@armlinux.org.uk>
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On Thu, Jan 25, 2024 at 6:04=E2=80=AFPM Andrew Morton <akpm@linux-foundatio=
n.org> wrote:
>
> On Mon, 22 Jan 2024 22:43:05 -0800 Suren Baghdasaryan <surenb@google.com>=
 wrote:
>
> > The change [1] missed ARM architecture when fixing major fault accounti=
ng
> > for page fault retry under per-VMA lock. Add missing code to fix ARM
> > architecture fault accounting.
> >
> > [1] 46e714c729c8 ("arch/mm/fault: fix major fault accounting when retry=
ing under per-VMA lock")
> >
> > Fixes: 12214eba1992 ("mm: handle read faults under the VMA lock")
>
> What are the userspace-visible runtime effects of this change?

The user-visible effects is that it restores correct major fault
accounting that was broken after [2] was merged in 6.7 kernel. The
more detailed description is in [3] and this patch simply adds the
same fix to ARM architecture which I missed in [3]. I can re-send the
patch with the full description from [3] if needed.

>
> Is a cc:stable backport desirable?

Yes, I guess since [2] was merged in 6.7, cc-ing stable would be desirable.
Please let me know if you want me to re-send the patch with full
description and CC'ing stable.

[2] https://lore.kernel.org/all/20231006195318.4087158-6-willy@infradead.or=
g/
[3] https://lore.kernel.org/all/20231226214610.109282-1-surenb@google.com/

>
> > Reported-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
> > Signed-off-by: Suren Baghdasaryan <surenb@google.com>