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Date:   Mon, 30 May 2022 10:41:42 +0100
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Subject: Re: [PATCH v6 04/22] drm/panfrost: Fix shrinker list corruption by
 madvise IOCTL
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To:     Dmitry Osipenko <dmitry.osipenko@collabora.com>,
        David Airlie <airlied@linux.ie>,
        Gerd Hoffmann <kraxel@redhat.com>,
        Gurchetan Singh <gurchetansingh@chromium.org>,
        Chia-I Wu <olvaffe@gmail.com>, Daniel Vetter <daniel@ffwll.ch>,
        Daniel Almeida <daniel.almeida@collabora.com>,
        Gert Wollny <gert.wollny@collabora.com>,
        Gustavo Padovan <gustavo.padovan@collabora.com>,
        Daniel Stone <daniel@fooishbar.org>,
        Tomeu Vizoso <tomeu.vizoso@collabora.com>,
        Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
        Maxime Ripard <mripard@kernel.org>,
        Thomas Zimmermann <tzimmermann@suse.de>,
        Rob Herring <robh@kernel.org>,
        Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>,
        Rob Clark <robdclark@gmail.com>,
        Emil Velikov <emil.l.velikov@gmail.com>,
        Robin Murphy <robin.murphy@arm.com>,
        Qiang Yu <yuq825@gmail.com>,
        Sumit Semwal <sumit.semwal@linaro.org>,
        =?UTF-8?Q?Christian_K=c3=b6nig?= <christian.koenig@amd.com>,
        "Pan, Xinhui" <Xinhui.Pan@amd.com>,
        Thierry Reding <thierry.reding@gmail.com>,
        Tomasz Figa <tfiga@chromium.org>,
        Marek Szyprowski <m.szyprowski@samsung.com>,
        Mauro Carvalho Chehab <mchehab@kernel.org>,
        Alex Deucher <alexander.deucher@amd.com>,
        Jani Nikula <jani.nikula@linux.intel.com>,
        Joonas Lahtinen <joonas.lahtinen@linux.intel.com>,
        Rodrigo Vivi <rodrigo.vivi@intel.com>,
        Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc:     dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org,
        virtualization@lists.linux-foundation.org,
        Dmitry Osipenko <digetx@gmail.com>,
        linux-tegra@vger.kernel.org, linux-media@vger.kernel.org,
        linaro-mm-sig@lists.linaro.org, amd-gfx@lists.freedesktop.org,
        intel-gfx@lists.freedesktop.org, kernel@collabora.com
References: <20220526235040.678984-1-dmitry.osipenko@collabora.com>
 <20220526235040.678984-5-dmitry.osipenko@collabora.com>
From:   Steven Price <steven.price@arm.com>
In-Reply-To: <20220526235040.678984-5-dmitry.osipenko@collabora.com>
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On 27/05/2022 00:50, 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>

Reviewed-by: Steven Price <steven.price@arm.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);
>  	}