ARM: OMAP1: ams-delta: Fix possible use of uninitialized field

BugLink: https://bugs.launchpad.net/bugs/1837161
[ 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>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>

diff --git a/arch/arm/mach-omap1/board-ams-delta.c b/arch/arm/mach-omap1/board-ams-delta.c
index 52e8e53ca154a7146a9abe2b4bf95bf2b2c2be8a..a63ba458ff2a5d23694611ddd0e85bf9bb20e0a4 100644 (file)
--- a/arch/arm/mach-omap1/board-ams-delta.c
+++ b/arch/arm/mach-omap1/board-ams-delta.c
@@ -512,6 +512,9 @@ static void modem_pm(struct uart_port *port, unsigned int state, unsigned old)
        struct modem_private_data *priv = port->private_data;
        int ret;
 
+       if (!priv)
+               return;
+
        if (IS_ERR(priv->regulator))
                return;