linux-kernel - Re: [PATCH] opp: Invalidate current opp when draining the opp list

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Date:   Thu, 4 Mar 2021 17:27:46 +0000
From:   Lukasz Luba <lukasz.luba@....com>
To:     Beata Michalska <beata.michalska@....com>,
        linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org
Cc:     vireshk@...nel.org, nm@...com, sboyd@...nel.org
Subject: Re: [PATCH] opp: Invalidate current opp when draining the opp list

Hi Beata,

On 3/4/21 3:07 PM, Beata Michalska wrote:
> The current_opp when set, grabs additional reference on the opp,
> which is then supposed to be dropped upon releasing the opp table.
> Still both dev_pm_opp_remove_table and dev_pm_opp_remove_all_dynamic
> will completely drain the OPPs list, including dropping the additional
> reference on current_opp. This may lead to an attempt to access
> memory that has already been released. Make sure that while draining
> the list (in both dynamic and static cases) the current_opp gets
> actually invalidated.
> 
> Fixes: 81c4d8a3c414 ("opp: Keep track of currently programmed OPP")
> 
> Signed-off-by: Beata Michalska <beata.michalska@....com>
> ---
>   drivers/opp/core.c | 49 ++++++++++++++++++++++++++++++++-----------------
>   1 file changed, 32 insertions(+), 17 deletions(-)

The change looks good.

Reviewed-by: Lukasz Luba <lukasz.luba@....com>

Regards,
Lukasz