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Subject: Re: [PATCH] drm: vkms: check status of alloc_ordered_workqueue
To:     Kangjie Lu <kjlu@umn.edu>
Cc:     pakki001@umn.edu, Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com>,
        Haneen Mohammed <hamohammed.sa@gmail.com>,
        Daniel Vetter <daniel@ffwll.ch>,
        David Airlie <airlied@linux.ie>,
        dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org
References: <20190309043628.6078-1-kjlu@umn.edu>
From:   Mukesh Ojha <mojha@codeaurora.org>
Message-ID: <955fbabe-e5f2-cfff-8dfd-1730243b0fff@codeaurora.org>
Date:   Sat, 23 Mar 2019 15:35:15 +0530
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On 3/9/2019 10:06 AM, Kangjie Lu wrote:
> alloc_ordered_workqueue may fail and return NULL.
> The fix returns ENOMEM when it fails to avoid potential NULL
> pointer dereference.
>
> Signed-off-by: Kangjie Lu <kjlu@umn.edu>
> ---
>   drivers/gpu/drm/vkms/vkms_crtc.c | 2 ++
>   1 file changed, 2 insertions(+)
>
> diff --git a/drivers/gpu/drm/vkms/vkms_crtc.c b/drivers/gpu/drm/vkms/vkms_crtc.c
> index 8a9aeb0a9ea8..bb66dbcd5e3f 100644
> --- a/drivers/gpu/drm/vkms/vkms_crtc.c
> +++ b/drivers/gpu/drm/vkms/vkms_crtc.c
> @@ -219,6 +219,8 @@ int vkms_crtc_init(struct drm_device *dev, struct drm_crtc *crtc,
>   	spin_lock_init(&vkms_out->state_lock);
>   
>   	vkms_out->crc_workq = alloc_ordered_workqueue("vkms_crc_workq", 0);
> +	if (!vkms_out->crc_workq)
> +		return -ENOMEM;
>   
>   	return ret;
>   }


Check the clean up path more carefully, you have undo which you have 
done successfully in drm_crtc_init_with_planes.


Thanks,
  Mukesh