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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, Janusz Krzysztofik <jmkrzyszt@gmail.com>,
        Tony Lindgren <tony@atomide.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.9 13/51] ARM: OMAP1: ams-delta: Fix possible use of uninitialized field
Date:   Fri, 14 Dec 2018 13:00:15 +0100
Message-Id: <20181214115714.522010480@linuxfoundation.org>
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4.9-stable review patch.  If anyone has any objections, please let me know.

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

[ Upstream commit cec83ff1241ec98113a19385ea9e9cfa9aa4125b ]

While playing with initialization order of modem device, it has been
discovered that under some circumstances (early console init, I
believe) its .pm() callback may be called before the
uart_port->private_data pointer is initialized from
plat_serial8250_port->private_data, resulting in NULL pointer
dereference.  Fix it by checking for uninitialized pointer before using
it in modem_pm().

Fixes: aabf31737a6a ("ARM: OMAP1: ams-delta: update the modem to use regulator API")
Signed-off-by: Janusz Krzysztofik <jmkrzyszt@gmail.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/arm/mach-omap1/board-ams-delta.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/arm/mach-omap1/board-ams-delta.c b/arch/arm/mach-omap1/board-ams-delta.c
index 6613a6ff5dbc..c4b634c54fbd 100644
--- a/arch/arm/mach-omap1/board-ams-delta.c
+++ b/arch/arm/mach-omap1/board-ams-delta.c
@@ -511,6 +511,9 @@ static void modem_pm(struct uart_port *port, unsigned int state, unsigned old)
 {
 	struct modem_private_data *priv = port->private_data;
 
+	if (!priv)
+		return;
+
 	if (IS_ERR(priv->regulator))
 		return;
 
-- 
2.19.1