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Date:   Thu, 17 Jun 2021 06:51:03 +0200
From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     Aman Priyadarshi <apeureka@amazon.de>
Cc:     Marc Zyngier <maz@kernel.org>, Will Deacon <will@kernel.org>,
        Alexander Graf <graf@amazon.de>,
        Mark Rutland <mark.rutland@arm.com>, stable@vger.kernel.org,
        Ali Saidi <alisaidi@amazon.com>
Subject: Re: [PATCH] arm64: perf: Disable PMU while processing counter
 overflows
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References: <YMoQ1MZgsL2hF2EL@kroah.com>
 <20210616192859.21708-1-apeureka@amazon.de>
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On Wed, Jun 16, 2021 at 09:28:59PM +0200, Aman Priyadarshi wrote:
> From: Suzuki K Poulose <suzuki.poulose@arm.com>
> 
> [ Upstream commit 3cce50dfec4a5b0414c974190940f47dd32c6dee ]
> 
> The arm64 PMU updates the event counters and reprograms the
> counters in the overflow IRQ handler without disabling the
> PMU. This could potentially cause skews in for group counters,
> where the overflowed counters may potentially loose some event
> counts, while they are reprogrammed. To prevent this, disable
> the PMU while we process the counter overflows and enable it
> right back when we are done.
> 
> This patch also moves the PMU stop/start routines to avoid a
> forward declaration.
> 
> Suggested-by: Mark Rutland <mark.rutland@arm.com>
> Cc: Will Deacon <will.deacon@arm.com>
> Acked-by: Mark Rutland <mark.rutland@arm.com>
> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
> Signed-off-by: Will Deacon <will.deacon@arm.com>
> Signed-off-by: Aman Priyadarshi <apeureka@amazon.de>
> Cc: stable@vger.kernel.org
> ---
>  arch/arm64/kernel/perf_event.c | 50 +++++++++++++++++++---------------
>  1 file changed, 28 insertions(+), 22 deletions(-)

What stable tree(s) do you want this applied to?

thanks,

greg k-h