Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
MIME-Version: 1.0
References: <1588314480-22409-1-git-send-email-mansur@codeaurora.org>
In-Reply-To: <1588314480-22409-1-git-send-email-mansur@codeaurora.org>
From:   Doug Anderson <dianders@chromium.org>
Date:   Mon, 1 Jun 2020 20:37:43 -0700
Message-ID: <CAD=FV=Vt8je1AtT8id-rPC3JToF_7uGKpC-uDuSpzCkwi3e4Sw@mail.gmail.com>
Subject: Re: [PATCH V2] venus: fix multiple encoder crash
To:     Mansur Alisha Shaik <mansur@codeaurora.org>
Cc:     stanimir.varbanov@linaro.org, LKML <linux-kernel@vger.kernel.org>,
        linux-arm-msm <linux-arm-msm@vger.kernel.org>,
        vgarodia@codeaurora.org
Content-Type: text/plain; charset="UTF-8"
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Hi,

On Thu, Apr 30, 2020 at 11:28 PM Mansur Alisha Shaik
<mansur@codeaurora.org> wrote:
>
> Currently we are considering the instances which are available
> in core->inst list for load calculation in min_loaded_core()
> function, but this is incorrect because by the time we call
> decide_core() for second instance, the third instance not
> filled yet codec_freq_data pointer.
>
> Solve this by considering the instances whose session has started.
>
> Signed-off-by: Mansur Alisha Shaik <mansur@codeaurora.org>
> ---
> Changes in V2:
> - As per Alex and Jeffrey comments, elaborated problem
>   and addressed review comments.
>
>  drivers/media/platform/qcom/venus/pm_helpers.c | 4 ++++
>  1 file changed, 4 insertions(+)

This fixes the same crash I reported here:

https://lore.kernel.org/r/20200601150314.RFC.1.I1e40623bbe8fa43ff1415fc273cba66503b9b048@changeid

Thus:

Fixes: eff82f79c562 ("media: venus: introduce core selection")
Tested-by: Douglas Anderson <dianders@chromium.org>

I still have the same reservations I expressed in the patch I posed
about whether this is truly safe from a locking point of view, but
certainly it puts us in a better state than we are today.

-Doug