[PATCH] drm/armada: fix device_node reference leak in armada_lcd_bind()

[PATCH] drm/armada: fix device_node reference leak in armada_lcd_bind()

[Wentao Liang]

In armada_lcd_bind(), of_get_child_by_name() obtains a reference to
the "port" device_node which is passed to armada_drm_crtc_create().
On success, the reference is transferred to the crtc structure and
released later. However, if armada_drm_crtc_create() fails, the
function returns directly without releasing the port node, causing a
reference leak.

Fix by adding of_node_put(port) in the error path.

Fixes: 9611cb93fa65 ("drm/armada: register crtc with port")
Cc: stable@vger.kernel.org
Signed-off-by: Wentao Liang <vulab@iscas.ac.cn>
---
 drivers/gpu/drm/armada/armada_crtc.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/armada/armada_crtc.c b/drivers/gpu/drm/armada/armada_crtc.c
index 0900e4466ffb..dfca664847b6 100644
--- a/drivers/gpu/drm/armada/armada_crtc.c
+++ b/drivers/gpu/drm/armada/armada_crtc.c
@@ -1035,7 +1035,10 @@ armada_lcd_bind(struct device *dev, struct device *master, void *data)
 		}
 	}
 
-	return armada_drm_crtc_create(drm, dev, res, irq, variant, port);
+	ret = armada_drm_crtc_create(drm, dev, res, irq, variant, port);
+	if (ret)
+		of_node_put(port);
+	return ret;
 }
 
 static void
-- 
2.34.1

Re: [PATCH] drm/armada: fix device_node reference leak in armada_lcd_bind()

[kernel test robot]

Hi Wentao,

kernel test robot noticed the following build warnings:

[auto build test WARNING on daeinki-drm-exynos/exynos-drm-next]
[also build test WARNING on drm/drm-next drm-i915/for-linux-next drm-i915/for-linux-next-fixes drm-misc/drm-misc-next drm-tip/drm-tip linus/master rmk-arm/drm-armada-devel v7.1-rc3 next-20260508]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Wentao-Liang/drm-armada-fix-device_node-reference-leak-in-armada_lcd_bind/20260512-194755
base:   https://git.kernel.org/pub/scm/linux/kernel/git/daeinki/drm-exynos.git exynos-drm-next
patch link:    https://lore.kernel.org/r/20260509091821.963513-1-vulab%40iscas.ac.cn
patch subject: [PATCH] drm/armada: fix device_node reference leak in armada_lcd_bind()
config: arm-randconfig-002-20260513 (https://download.01.org/0day-ci/archive/20260513/202605130528.fPiFL3HJ-lkp@intel.com/config)
compiler: arm-linux-gnueabi-gcc (GCC) 14.3.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260513/202605130528.fPiFL3HJ-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202605130528.fPiFL3HJ-lkp@intel.com/

All warnings (new ones prefixed by >>):

   drivers/gpu/drm/armada/armada_crtc.c: In function 'armada_lcd_bind':
   drivers/gpu/drm/armada/armada_crtc.c:1039:9: error: 'ret' undeclared (first use in this function); did you mean 'res'?
    1039 |         ret = armada_drm_crtc_create(drm, dev, res, irq, variant, port);
         |         ^~~
         |         res
   drivers/gpu/drm/armada/armada_crtc.c:1039:9: note: each undeclared identifier is reported only once for each function it appears in
>> drivers/gpu/drm/armada/armada_crtc.c:1043:1: warning: control reaches end of non-void function [-Wreturn-type]
    1043 | }
         | ^


vim +1043 drivers/gpu/drm/armada/armada_crtc.c

d8c96083cf5e4a Russell King 2014-04-22  1007  
d8c96083cf5e4a Russell King 2014-04-22  1008  static int
d8c96083cf5e4a Russell King 2014-04-22  1009  armada_lcd_bind(struct device *dev, struct device *master, void *data)
d8c96083cf5e4a Russell King 2014-04-22  1010  {
d8c96083cf5e4a Russell King 2014-04-22  1011  	struct platform_device *pdev = to_platform_device(dev);
d8c96083cf5e4a Russell King 2014-04-22  1012  	struct drm_device *drm = data;
d8c96083cf5e4a Russell King 2014-04-22  1013  	struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
d8c96083cf5e4a Russell King 2014-04-22  1014  	int irq = platform_get_irq(pdev, 0);
d8c96083cf5e4a Russell King 2014-04-22  1015  	const struct armada_variant *variant;
9611cb93fa65dd Russell King 2014-06-15  1016  	struct device_node *port = NULL;
e1704914867872 Rob Herring  2023-10-20  1017  	struct device_node *np, *parent = dev->of_node;
d8c96083cf5e4a Russell King 2014-04-22  1018  
d8c96083cf5e4a Russell King 2014-04-22  1019  	if (irq < 0)
d8c96083cf5e4a Russell King 2014-04-22  1020  		return irq;
d8c96083cf5e4a Russell King 2014-04-22  1021  
d8c96083cf5e4a Russell King 2014-04-22  1022  
e1704914867872 Rob Herring  2023-10-20  1023  	variant = device_get_match_data(dev);
e1704914867872 Rob Herring  2023-10-20  1024  	if (!variant)
d8c96083cf5e4a Russell King 2014-04-22  1025  		return -ENXIO;
d8c96083cf5e4a Russell King 2014-04-22  1026  
e1704914867872 Rob Herring  2023-10-20  1027  	if (parent) {
9611cb93fa65dd Russell King 2014-06-15  1028  		np = of_get_child_by_name(parent, "ports");
9611cb93fa65dd Russell King 2014-06-15  1029  		if (np)
9611cb93fa65dd Russell King 2014-06-15  1030  			parent = np;
9611cb93fa65dd Russell King 2014-06-15  1031  		port = of_get_child_by_name(parent, "port");
9611cb93fa65dd Russell King 2014-06-15  1032  		of_node_put(np);
9611cb93fa65dd Russell King 2014-06-15  1033  		if (!port) {
4bf99144d2b407 Rob Herring  2017-07-18  1034  			dev_err(dev, "no port node found in %pOF\n", parent);
9611cb93fa65dd Russell King 2014-06-15  1035  			return -ENXIO;
9611cb93fa65dd Russell King 2014-06-15  1036  		}
d8c96083cf5e4a Russell King 2014-04-22  1037  	}
d8c96083cf5e4a Russell King 2014-04-22  1038  
2627b8898b0e61 Wentao Liang 2026-05-09  1039  	ret = armada_drm_crtc_create(drm, dev, res, irq, variant, port);
2627b8898b0e61 Wentao Liang 2026-05-09  1040  	if (ret)
2627b8898b0e61 Wentao Liang 2026-05-09  1041  		of_node_put(port);
2627b8898b0e61 Wentao Liang 2026-05-09  1042  	return ret;
d8c96083cf5e4a Russell King 2014-04-22 @1043  }
d8c96083cf5e4a Russell King 2014-04-22  1044  

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki