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Thu, 30 Oct 2025 15:54:39 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=dkim; t=1761836081; h=from:subject:date:message-id:to:cc:mime-version:content-type: content-transfer-encoding:content-language:in-reply-to:references:autocrypt; bh=jJ76TtYiUacoq5HrWzXg1ucBLVjx6zmnX1RJS69c9wI=; b=YLyBq7ZVSCxrOz9I4Wm6G6sYyeY4yoO9GjAaclMLekpQLKWrY6QwkHxs+rQewkchnztuqy sfE6vesaEcDqMn/KclRkcg4/c0JFe3iku/O1hNHr3hF0YGe4QhdWcYly0VsDLAApnV+D9T 47NzoT6TpR76k2PjNgx4/ZJo6MFlC0d7tdUc/2hhpsfPJUQGRiHKTFpv52jHMRpvJHJlTW mUmHDSOBcRnNKjHSvBwcg8LpgFaYvWOvK4SN8oLJUBvz6LN5DGU4pjh6x/HLJEg5P4uoPT 8xayKuURX1z/ouuB+l9S1kS3Z4gHBnNyQzrQogDSXTP2tiua/ubauTct0MpKUQ== Message-ID: <8725fc5b-4d29-4fa5-9227-6755fdd9a2e0@bootlin.com> Date: Thu, 30 Oct 2025 15:54:38 +0100 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 3/3] drm/display: bridge_connector: get/put the panel_bridge To: Luca Ceresoli , Marek Szyprowski , Naresh Kamboju , Andrzej Hajda , Neil Armstrong , Robert Foss , Laurent Pinchart , Jonas Karlman , Jernej Skrabec , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Simona Vetter , Dmitry Baryshkov Cc: Hui Pu , Thomas Petazzoni , dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org References: <20251017-drm-bridge-alloc-getput-bridge-connector-fix-hdmi_cec-v2-0-667abf6d47c0@bootlin.com> <20251017-drm-bridge-alloc-getput-bridge-connector-fix-hdmi_cec-v2-3-667abf6d47c0@bootlin.com> Content-Language: en-US, fr From: Louis Chauvet Autocrypt: addr=louis.chauvet@bootlin.com; 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charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Last-TLS-Session-Version: TLSv1.3 Le 17/10/2025 à 18:15, Luca Ceresoli a écrit : > The panel_bridge pointer is taken inside the loop and used after the > loop. Being a local variable, use a cleanup action to ensure it is put on > return. > > Based on the code structure the panel_bridge pointer might be assigned > during multiple loop iterations. Even though this is probably not possible > in the practice, ensure there is no reference leak by putting the reference > to the old value before overwriting with the new value. > > Signed-off-by: Luca Ceresoli Reviewed-by: Louis Chauvet > --- > > This patch was added in v2: > - taking the panel_bridge specific code from the original (buggy) patch, > and split it for clarity from the larger patch covering stored bridge > pointers > - comapred to the original code, added drm_bridge_put() for extra safety > even though likely not necessary > --- > drivers/gpu/drm/display/drm_bridge_connector.c | 8 +++++--- > 1 file changed, 5 insertions(+), 3 deletions(-) > > diff --git a/drivers/gpu/drm/display/drm_bridge_connector.c b/drivers/gpu/drm/display/drm_bridge_connector.c > index 95ccf86527129edaa6fcc75c6202985e73c46da8..a2d30cf9e06df44b89456b5aba8198ee1e5d5601 100644 > --- a/drivers/gpu/drm/display/drm_bridge_connector.c > +++ b/drivers/gpu/drm/display/drm_bridge_connector.c > @@ -652,7 +652,7 @@ struct drm_connector *drm_bridge_connector_init(struct drm_device *drm, > struct drm_bridge_connector *bridge_connector; > struct drm_connector *connector; > struct i2c_adapter *ddc = NULL; > - struct drm_bridge *panel_bridge = NULL; > + struct drm_bridge *panel_bridge __free(drm_bridge_put) = NULL; > unsigned int supported_formats = BIT(HDMI_COLORSPACE_RGB); > unsigned int max_bpc = 8; > bool support_hdcp = false; > @@ -787,8 +787,10 @@ struct drm_connector *drm_bridge_connector_init(struct drm_device *drm, > if (bridge->ddc) > ddc = bridge->ddc; > > - if (drm_bridge_is_panel(bridge)) > - panel_bridge = bridge; > + if (drm_bridge_is_panel(bridge)) { > + drm_bridge_put(panel_bridge); > + panel_bridge = drm_bridge_get(bridge); > + } > > if (bridge->support_hdcp) > support_hdcp = true; > -- -- Louis Chauvet, Bootlin Embedded Linux and Kernel engineering https://bootlin.com