linux-kernel - [PATCH 07/10] nvmem: core: fix device node refcounting

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Date:   Fri, 27 Jan 2023 10:40:12 +0000
From:   Srinivas Kandagatla <srinivas.kandagatla@...aro.org>
To:     gregkh@...uxfoundation.org
Cc:     linux-kernel@...r.kernel.org, Michael Walle <michael@...le.cc>,
        stable@...r.kernel.org,
        Srinivas Kandagatla <srinivas.kandagatla@...aro.org>
Subject: [PATCH 07/10] nvmem: core: fix device node refcounting

From: Michael Walle <michael@...le.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.

Cc: stable@...r.kernel.org
Fixes: 69aba7948cbe("nvmem: Add a simple NVMEM framework for consumers")
Fixes: 7ae6478b304b ("nvmem: core: rework nvmem cell instance creation")
Signed-off-by: Michael Walle <michael@...le.cc>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@...aro.org>
---
 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 e92c6f1aadbb..cbe5df99db82 100644
--- a/drivers/nvmem/core.c
+++ b/drivers/nvmem/core.c
@@ -1237,16 +1237,21 @@ 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);
-- 
2.25.1