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Message-ID: <78f3a73d-3c2a-4432-8ac5-9e4418f509cb@redhat.com>
Date:   Thu, 12 Oct 2023 19:58:01 +0200
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User-Agent: Mozilla Thunderbird
Subject: Re: [PATCH] drm/nouveau/dispnv04: fix a possible null pointer
 dereference
Content-Language: en-US
To:     Ma Ke <make_ruc2021@163.com>
Cc:     kherbst@redhat.com, lyude@redhat.com, airlied@gmail.com,
        daniel@ffwll.ch, noralf@tronnes.org, tzimmermann@suse.de,
        mripard@kernel.org, jani.nikula@intel.com,
        nouveau@lists.freedesktop.org, linux-kernel@vger.kernel.org,
        dri-devel@lists.freedesktop.org
References: <20231007032349.3997387-1-make_ruc2021@163.com>
From:   Danilo Krummrich <dakr@redhat.com>
Organization: RedHat
In-Reply-To: <20231007032349.3997387-1-make_ruc2021@163.com>
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On 10/7/23 05:23, Ma Ke wrote:
> In nv17_tv_get_ld_modes(), the return value of drm_mode_duplicate()
> is assigned to mode, which will lead to a NULL pointer dereference
> on failure of drm_mode_duplicate(). Add a check to avoid npd.
> 
> Signed-off-by: Ma Ke <make_ruc2021@163.com>

Reviewed-by: Danilo Krummrich <dakr@redhat.com>

> ---
>   drivers/gpu/drm/nouveau/dispnv04/tvnv17.c | 2 ++
>   1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/gpu/drm/nouveau/dispnv04/tvnv17.c b/drivers/gpu/drm/nouveau/dispnv04/tvnv17.c
> index 670c9739e5e1..4a08e61f3336 100644
> --- a/drivers/gpu/drm/nouveau/dispnv04/tvnv17.c
> +++ b/drivers/gpu/drm/nouveau/dispnv04/tvnv17.c
> @@ -209,6 +209,8 @@ static int nv17_tv_get_ld_modes(struct drm_encoder *encoder,
>   		struct drm_display_mode *mode;
>   
>   		mode = drm_mode_duplicate(encoder->dev, tv_mode);
> +		if (!mode)
> +			continue;
>   
>   		mode->clock = tv_norm->tv_enc_mode.vrefresh *
>   			mode->htotal / 1000 *