Re: [PATCH] arm64: perf: Disable PMU while processing counter overflows

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

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