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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, Kangjie Lu <kjlu@umn.edu>
Subject: [PATCH 4.19 078/134] tty: mxs-auart: fix a potential NULL pointer dereference
Date:   Mon,  1 Apr 2019 19:01:54 +0200
Message-Id: <20190401170051.688270055@linuxfoundation.org>
In-Reply-To: <20190401170044.243719205@linuxfoundation.org>
References: <20190401170044.243719205@linuxfoundation.org>
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4.19-stable review patch.  If anyone has any objections, please let me know.

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

From: Kangjie Lu <kjlu@umn.edu>

commit 6734330654dac550f12e932996b868c6d0dcb421 upstream.

In case ioremap fails, the fix returns -ENOMEM to avoid NULL
pointer dereferences.
Multiple places use port.membase.

Signed-off-by: Kangjie Lu <kjlu@umn.edu>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/tty/serial/mxs-auart.c |    4 ++++
 1 file changed, 4 insertions(+)

--- a/drivers/tty/serial/mxs-auart.c
+++ b/drivers/tty/serial/mxs-auart.c
@@ -1685,6 +1685,10 @@ static int mxs_auart_probe(struct platfo
 
 	s->port.mapbase = r->start;
 	s->port.membase = ioremap(r->start, resource_size(r));
+	if (!s->port.membase) {
+		ret = -ENOMEM;
+		goto out_disable_clks;
+	}
 	s->port.ops = &mxs_auart_ops;
 	s->port.iotype = UPIO_MEM;
 	s->port.fifosize = MXS_AUART_FIFO_SIZE;