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Date:   Thu, 1 Jun 2023 11:22:46 +0100
From:   Greg KH <gregkh@linuxfoundation.org>
To:     Wyes Karny <wyes.karny@amd.com>
Cc:     stable@vger.kernel.org,
        "Gautham R. Shenoy" <gautham.shenoy@amd.com>,
        "Rafael J . Wysocki" <rafael.j.wysocki@intel.com>
Subject: Re: [PATCH 6.3.y] cpufreq: amd-pstate: Add ->fast_switch() callback
Message-ID: <2023060137-mating-bucked-6b32@gregkh>
References: <2023052858-danger-kilowatt-29cc@gregkh>
 <20230530115503.3702-1-wyes.karny@amd.com>
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On Tue, May 30, 2023 at 11:55:03AM +0000, Wyes Karny wrote:
> From: "Gautham R. Shenoy" <gautham.shenoy@amd.com>
> 
> [ Upstream commit 4badf2eb1e986bdbf34dd2f5d4c979553a86fe54 ]
> 
> Schedutil normally calls the adjust_perf callback for drivers with
> adjust_perf callback available and fast_switch_possible flag set.
> However, when frequency invariance is disabled and schedutil tries to
> invoke fast_switch. So, there is a chance of kernel crash if this
> function pointer is not set. To protect against this scenario add
> fast_switch callback to amd_pstate driver.
> 
> Fixes: 1d215f0319c2 ("cpufreq: amd-pstate: Add fast switch function for AMD P-State")
> Signed-off-by: Gautham R. Shenoy <gautham.shenoy@amd.com>
> Signed-off-by: Wyes Karny <wyes.karny@amd.com>
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> (cherry picked from commit 4badf2eb1e986bdbf34dd2f5d4c979553a86fe54)
> ---
>  drivers/cpufreq/amd-pstate.c | 37 +++++++++++++++++++++++++++++-------
>  1 file changed, 30 insertions(+), 7 deletions(-)

All now queued up, thanks.

greg k-h