[PATCH] memory: jz4780_nemc: Fix potential NULL dereference in jz4780_nemc_probe()

From: Zhang Changzhong <zhangchangzhong@huawei.com>
To: Paul Cercueil <paul@crapouillou.net>,
	Krzysztof Kozlowski <krzk@kernel.org>,
	Zubair Lutfullah Kakakhel <Zubair.Kakakhel@imgtec.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Alex Smith <alex.smith@imgtec.com>
Cc: Zhang Changzhong <zhangchangzhong@huawei.com>,
	<linux-kernel@vger.kernel.org>
Subject: [PATCH] memory: jz4780_nemc: Fix potential NULL dereference in jz4780_nemc_probe()
Date: Fri, 4 Dec 2020 16:31:57 +0800	[thread overview]
Message-ID: <1607070717-32880-1-git-send-email-zhangchangzhong@huawei.com> (raw)

platform_get_resource() may fail and return NULL, so we should
better check it's return value to avoid a NULL pointer dereference
a bit later in the code.

This is detected by Coccinelle semantic patch.

@@
expression pdev, res, n, t, e, e1, e2;
@@

res = \(platform_get_resource\|platform_get_resource_byname\)(pdev, t,
n);
+ if (!res)
+   return -EINVAL;
... when != res == NULL
e = devm_ioremap(e1, res->start, e2);

Fixes: 911a88829725 ("memory: jz4780-nemc: driver for the NEMC on JZ4780 SoCs")
Signed-off-by: Zhang Changzhong <zhangchangzhong@huawei.com>
---
 drivers/memory/jz4780-nemc.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/memory/jz4780-nemc.c b/drivers/memory/jz4780-nemc.c
index 3ec5cb0..465ea92 100644
--- a/drivers/memory/jz4780-nemc.c
+++ b/drivers/memory/jz4780-nemc.c
@@ -291,6 +291,8 @@ static int jz4780_nemc_probe(struct platform_device *pdev)
 	nemc->dev = dev;
 
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!res)
+		return -EINVAL;
 
 	/*
 	 * The driver currently only uses the registers up to offset
-- 
2.9.5

