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Date:   Fri, 27 May 2022 11:56:36 -0400
From:   Alyssa Rosenzweig <alyssa@collabora.com>
To:     Dmitry Osipenko <dmitry.osipenko@collabora.com>
Cc:     David Airlie <airlied@linux.ie>, Gerd Hoffmann <kraxel@redhat.com>,
        Gurchetan Singh <gurchetansingh@chromium.org>,
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        Tomeu Vizoso <tomeu.vizoso@collabora.com>,
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        Thomas Zimmermann <tzimmermann@suse.de>,
        Rob Herring <robh@kernel.org>,
        Steven Price <steven.price@arm.com>,
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        Rob Clark <robdclark@gmail.com>,
        Emil Velikov <emil.l.velikov@gmail.com>,
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        Sumit Semwal <sumit.semwal@linaro.org>,
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        Dmitry Osipenko <digetx@gmail.com>,
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Subject: Re: [PATCH v6 04/22] drm/panfrost: Fix shrinker list corruption by
 madvise IOCTL
Message-ID: <YpD0tCuCd7HzwWg6@maud>
References: <20220526235040.678984-1-dmitry.osipenko@collabora.com>
 <20220526235040.678984-5-dmitry.osipenko@collabora.com>
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Acked-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>

On Fri, May 27, 2022 at 02:50:22AM +0300, Dmitry Osipenko wrote:
> Calling madvise IOCTL twice on BO causes memory shrinker list corruption
> and crashes kernel because BO is already on the list and it's added to
> the list again, while BO should be removed from from the list before it's
> re-added. Fix it.
> 
> Cc: stable@vger.kernel.org
> Fixes: 013b65101315 ("drm/panfrost: Add madvise and shrinker support")
> Signed-off-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
> ---
>  drivers/gpu/drm/panfrost/panfrost_drv.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/panfrost/panfrost_drv.c b/drivers/gpu/drm/panfrost/panfrost_drv.c
> index 087e69b98d06..b1e6d238674f 100644
> --- a/drivers/gpu/drm/panfrost/panfrost_drv.c
> +++ b/drivers/gpu/drm/panfrost/panfrost_drv.c
> @@ -433,8 +433,8 @@ static int panfrost_ioctl_madvise(struct drm_device *dev, void *data,
>  
>  	if (args->retained) {
>  		if (args->madv == PANFROST_MADV_DONTNEED)
> -			list_add_tail(&bo->base.madv_list,
> -				      &pfdev->shrinker_list);
> +			list_move_tail(&bo->base.madv_list,
> +				       &pfdev->shrinker_list);
>  		else if (args->madv == PANFROST_MADV_WILLNEED)
>  			list_del_init(&bo->base.madv_list);
>  	}
> -- 
> 2.35.3
>