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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        Evan Nimmo <evan.nimmo@alliedtelesis.co.nz>,
        Rob Herring <robh@kernel.org>, Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.19 060/101] of/address: Fix of_node memory leak in of_dma_is_coherent
Date:   Tue, 17 Nov 2020 14:05:27 +0100
Message-Id: <20201117122116.028079051@linuxfoundation.org>
In-Reply-To: <20201117122113.128215851@linuxfoundation.org>
References: <20201117122113.128215851@linuxfoundation.org>
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From: Evan Nimmo <evan.nimmo@alliedtelesis.co.nz>

[ Upstream commit a5bea04fcc0b3c0aec71ee1fd58fd4ff7ee36177 ]

Commit dabf6b36b83a ("of: Add OF_DMA_DEFAULT_COHERENT & select it on
powerpc") added a check to of_dma_is_coherent which returns early
if OF_DMA_DEFAULT_COHERENT is enabled. This results in the of_node_put()
being skipped causing a memory leak. Moved the of_node_get() below this
check so we now we only get the node if OF_DMA_DEFAULT_COHERENT is not
enabled.

Fixes: dabf6b36b83a ("of: Add OF_DMA_DEFAULT_COHERENT & select it on powerpc")
Signed-off-by: Evan Nimmo <evan.nimmo@alliedtelesis.co.nz>
Link: https://lore.kernel.org/r/20201110022825.30895-1-evan.nimmo@alliedtelesis.co.nz
Signed-off-by: Rob Herring <robh@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/of/address.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/of/address.c b/drivers/of/address.c
index c42aebba35ab8..30806dd357350 100644
--- a/drivers/of/address.c
+++ b/drivers/of/address.c
@@ -975,11 +975,13 @@ EXPORT_SYMBOL_GPL(of_dma_get_range);
  */
 bool of_dma_is_coherent(struct device_node *np)
 {
-	struct device_node *node = of_node_get(np);
+	struct device_node *node;
 
 	if (IS_ENABLED(CONFIG_OF_DMA_DEFAULT_COHERENT))
 		return true;
 
+	node = of_node_get(np);
+
 	while (node) {
 		if (of_property_read_bool(node, "dma-coherent")) {
 			of_node_put(node);
-- 
2.27.0