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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, Aditya Pakki <pakki001@umn.edu>
Subject: [PATCH 4.4 114/131] serial: max310x: Fix to avoid potential NULL pointer dereference
Date:   Mon,  1 Apr 2019 19:03:04 +0200
Message-Id: <20190401170101.207997696@linuxfoundation.org>
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4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Aditya Pakki <pakki001@umn.edu>

commit 3a10e3dd52e80b9a97a3346020024d17b2c272d6 upstream.

of_match_device can return a NULL pointer when matching device is not
found. This patch avoids a scenario causing NULL pointer derefernce.

Signed-off-by: Aditya Pakki <pakki001@umn.edu>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/tty/serial/max310x.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/drivers/tty/serial/max310x.c
+++ b/drivers/tty/serial/max310x.c
@@ -1306,6 +1306,8 @@ static int max310x_spi_probe(struct spi_
 	if (spi->dev.of_node) {
 		const struct of_device_id *of_id =
 			of_match_device(max310x_dt_ids, &spi->dev);
+		if (!of_id)
+			return -ENODEV;
 
 		devtype = (struct max310x_devtype *)of_id->data;
 	} else {