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From:   David Lechner <david@lechnology.com>
To:     linux-arm-kernel@lists.infradead.org
Cc:     David Lechner <david@lechnology.com>, Sekhar Nori <nsekhar@ti.com>,
        Kevin Hilman <khilman@kernel.org>,
        Bartosz Golaszewski <bgolaszewski@baylibre.com>,
        linux-kernel@vger.kernel.org
Subject: [PATCH] ARM: davinci: DA8XX: fix oops in USB PHY driver due to stack allocated platform platform_data
Date:   Thu, 15 Mar 2018 13:02:56 -0500
Message-Id: <1521136976-32730-1-git-send-email-david@lechnology.com>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

This fixes a possible kernel oops due to using stack allocated platform
data for the USB PHY driver on DA8XX devices. If the platform device
probe is deferred, then we get a corrupt pointer for the platform data.

We now use a global static struct for the platform data so that the
platform data pointer does not get written over.

Tested on OMAP-L138 LCDK board using legacy board file.

Fixes: 9b504750923cb ("ARM: davinci: da8xx: Add USB PHY platform device")
Signed-off-by: David Lechner <david@lechnology.com>
---
 arch/arm/mach-davinci/usb-da8xx.c | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/arch/arm/mach-davinci/usb-da8xx.c b/arch/arm/mach-davinci/usb-da8xx.c
index b1e53e31..9ff9624 100644
--- a/arch/arm/mach-davinci/usb-da8xx.c
+++ b/arch/arm/mach-davinci/usb-da8xx.c
@@ -23,17 +23,20 @@
 #define DA8XX_USB0_BASE		0x01e00000
 #define DA8XX_USB1_BASE		0x01e25000
 
+static struct da8xx_usb_phy_platform_data da8xx_usb_phy_pdata;
+
 static struct platform_device da8xx_usb_phy = {
 	.name		= "da8xx-usb-phy",
 	.id		= -1,
+	.dev		= {
+		.platform_data	= &da8xx_usb_phy_pdata,
+	},
 };
 
+
 int __init da8xx_register_usb_phy(void)
 {
-	struct da8xx_usb_phy_platform_data pdata;
-
-	pdata.cfgchip = da8xx_get_cfgchip();
-	da8xx_usb_phy.dev.platform_data = &pdata;
+	da8xx_usb_phy_pdata.cfgchip = da8xx_get_cfgchip();
 
 	return platform_device_register(&da8xx_usb_phy);
 }
-- 
2.7.4