[PATCH v2] fsl/fman: Fix fm_node reference leak in read_dts_node()

[Wentao Liang <vulab@iscas.ac.cn>]

of_node_get() takes a reference on the FMan device node. That reference
is released neither on the success path, which returns straight after
of_platform_populate(), nor on the failure paths that jump to fman_free
without going through fman_node_put(). Neither read_dts_node() nor its
caller keeps fm_node around to release it later.

Release the reference on the success path, and route the remaining
failure paths through fman_node_put(). The latter leaves the fman_free
label without any user, so drop it as well: fman_node_put already falls
through to kfree(fman).

The candidate was found with static analysis tools; DeepSeek and GPT-6.1
Sol were used to audit it and to help prepare this fix.

Fixes: ecb239d96d36 ("ethernet: fman: fix wrong of_node_put() in probe function")
Cc: stable@vger.kernel.org
Signed-off-by: Wentao Liang <vulab@iscas.ac.cn>
---
Changes in v2:
- Remove the fman_free label, which no longer has a user once the failure
  paths go through fman_node_put(). With W=1 the leftover label is an
  -Werror=unused-label build failure, as Simon reported.
- Rebuilt with W=1 on v7.4-rc1 (x86_64 defconfig + COMPILE_TEST,
  CONFIG_FSL_FMAN=m); drivers/net/ethernet/freescale/fman/ now builds
  without warnings.
- Link to v1: https://lore.kernel.org/all/20260917110342.2148155-1-vulab@iscas.ac.cn/
- Sorry for the late reply, and thanks for catching the build failure.

 drivers/net/ethernet/freescale/fman/fman.c | 15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

diff --git a/drivers/net/ethernet/freescale/fman/fman.c b/drivers/net/ethernet/freescale/fman/fman.c
index 46cc28895e56..5507002097fd 100644
--- a/drivers/net/ethernet/freescale/fman/fman.c
+++ b/drivers/net/ethernet/freescale/fman/fman.c
@@ -2760,7 +2760,7 @@ static struct fman *read_dts_node(struct platform_device *of_dev)
 		err = -EINVAL;
 		dev_err(&of_dev->dev, "%s: could not find MURAM node\n",
 			__func__);
-		goto fman_free;
+		goto fman_node_put;
 	}
 
 	err = of_address_to_resource(muram_node, 0,
@@ -2769,7 +2769,7 @@ static struct fman *read_dts_node(struct platform_device *of_dev)
 		of_node_put(muram_node);
 		dev_err(&of_dev->dev, "%s: of_address_to_resource() = %d\n",
 			__func__, err);
-		goto fman_free;
+		goto fman_node_put;
 	}
 
 	of_node_put(muram_node);
@@ -2779,7 +2779,7 @@ static struct fman *read_dts_node(struct platform_device *of_dev)
 	if (err < 0) {
 		dev_err(&of_dev->dev, "%s: irq %d allocation failed (error = %d)\n",
 			__func__, irq, err);
-		goto fman_free;
+		goto fman_node_put;
 	}
 
 	if (fman->dts_params.err_irq != 0) {
@@ -2789,7 +2789,7 @@ static struct fman *read_dts_node(struct platform_device *of_dev)
 		if (err < 0) {
 			dev_err(&of_dev->dev, "%s: irq %d allocation failed (error = %d)\n",
 				__func__, fman->dts_params.err_irq, err);
-			goto fman_free;
+			goto fman_node_put;
 		}
 	}
 
@@ -2797,7 +2797,7 @@ static struct fman *read_dts_node(struct platform_device *of_dev)
 	if (IS_ERR(base_addr)) {
 		err = PTR_ERR(base_addr);
 		dev_err(&of_dev->dev, "%s: devm_ioremap() failed\n", __func__);
-		goto fman_free;
+		goto fman_node_put;
 	}
 
 	fman->dts_params.base_addr = base_addr;
@@ -2809,7 +2809,7 @@ static struct fman *read_dts_node(struct platform_device *of_dev)
 	if (err) {
 		dev_err(&of_dev->dev, "%s: of_platform_populate() failed\n",
 			__func__);
-		goto fman_free;
+		goto fman_node_put;
 	}
 
 #ifdef CONFIG_DPAA_ERRATUM_A050385
@@ -2817,11 +2817,12 @@ static struct fman *read_dts_node(struct platform_device *of_dev)
 		of_property_read_bool(fm_node, "fsl,erratum-a050385");
 #endif
 
+	of_node_put(fm_node);
+
 	return fman;
 
 fman_node_put:
 	of_node_put(fm_node);
-fman_free:
 	kfree(fman);
 	return ERR_PTR(err);
 }
-- 
2.43.0