[PATCH v3 03/18] nvmem: core: fix device node refcounting

From: Michael Walle <michael@walle.cc>
To: Jonathan Corbet <corbet@lwn.net>,
	Srinivas Kandagatla <srinivas.kandagatla@linaro.org>,
	Miquel Raynal <miquel.raynal@bootlin.com>,
	Rob Herring <robh+dt@kernel.org>,
	Frank Rowand <frowand.list@gmail.com>
Cc: linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org, devicetree@vger.kernel.org,
	Michael Walle <michael@walle.cc>
Subject: [PATCH v3 03/18] nvmem: core: fix device node refcounting
Date: Fri, 18 Nov 2022 19:51:03 +0100	[thread overview]
Message-ID: <20221118185118.1190044-4-michael@walle.cc> (raw)
In-Reply-To: <20221118185118.1190044-1-michael@walle.cc>

In of_nvmem_cell_get(), of_get_next_parent() is used on cell_np. This
will decrement the refcount on cell_np, but cell_np is still used later
in the code. Use of_get_parent() instead and of_node_put() in the
appropriate places.

Signed-off-by: Michael Walle <michael@walle.cc>
---
changes since v2:
 - new patch

 drivers/nvmem/core.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c
index 321d7d63e068..205a427f564d 100644
--- a/drivers/nvmem/core.c
+++ b/drivers/nvmem/core.c
@@ -1242,16 +1242,21 @@ struct nvmem_cell *of_nvmem_cell_get(struct device_node *np, const char *id)
 	if (!cell_np)
 		return ERR_PTR(-ENOENT);
 
-	nvmem_np = of_get_next_parent(cell_np);
-	if (!nvmem_np)
+	nvmem_np = of_get_parent(cell_np);
+	if (!nvmem_np) {
+		of_node_put(cell_np);
 		return ERR_PTR(-EINVAL);
+	}
 
 	nvmem = __nvmem_device_get(nvmem_np, device_match_of_node);
 	of_node_put(nvmem_np);
-	if (IS_ERR(nvmem))
+	if (IS_ERR(nvmem)) {
+		of_node_put(cell_np);
 		return ERR_CAST(nvmem);
+	}
 
 	cell_entry = nvmem_find_cell_entry_by_node(nvmem, cell_np);
+	of_node_put(cell_np);
 	if (!cell_entry) {
 		__nvmem_device_put(nvmem);
 		return ERR_PTR(-ENOENT);
-- 
2.30.2

