Subject: Re: [PATCH 1/2] drm/meson: Fix invalid pointer in meson_drv_unbind()

From: Neil Armstrong <[email-masked]>
Date: Sat, 23 Mar 2019 10:53:41 +0100

Hi Jean-Philippe,

Le 22/03/2019 16:26, Jean-Philippe Brucker a écrit :
> meson_drv_bind() registers a meson_drm struct as the device's privdata,
> but meson_drv_unbind() tries to retrieve a drm_device. This may cause a
> segfault on shutdown:
> 
> [ 5194.593429] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000197
>  ...
> [ 5194.788850] Call trace:
> [ 5194.791349]  drm_dev_unregister+0x1c/0x118 [drm]
> [ 5194.795848]  meson_drv_unbind+0x50/0x78 [meson_drm]
> 
> Retrieve the right pointer in meson_drv_unbind().
> 
> Fixes: bbbe775ec5b5 ("drm: Add support for Amlogic Meson Graphic Controller")
> Signed-off-by: Jean-Philippe Brucker <[email-masked]>

Thanks for working on this,
Acked-by: Neil Armstrong <[email-masked]>

I'll push it on drm-misc-fixes

> ---
>  drivers/gpu/drm/meson/meson_drv.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/meson/meson_drv.c b/drivers/gpu/drm/meson/meson_drv.c
> index 2281ed3eb774..7e85802c5398 100644
> --- a/drivers/gpu/drm/meson/meson_drv.c
> +++ b/drivers/gpu/drm/meson/meson_drv.c
> @@ -356,8 +356,8 @@ static int meson_drv_bind(struct device *dev)
>  
>  static void meson_drv_unbind(struct device *dev)
>  {
> -	struct drm_device *drm = dev_get_drvdata(dev);
> -	struct meson_drm *priv = drm->dev_private;
> +	struct meson_drm *priv = dev_get_drvdata(dev);
> +	struct drm_device *drm = priv->drm;
>  
>  	if (priv->canvas) {
>  		meson_canvas_free(priv->canvas, priv->canvas_id_osd1);
> 

_______________________________________________
linux-arm-kernel mailing list
[email-masked]
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel