[PATCH 4.4 34/87] usb: musb: ux500: Fix NULL pointer dereference at system PM

[Greg Kroah-Hartman]

4.4-stable review patch.  If anyone has any objections, please let me know.

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

From: Ulf Hansson <ulf.hansson@xxxxxxxxxx>

commit 79c5623f1cb85f33403eb9f1e45124e9f56181f8 upstream.

The commit 7d32cdef5356 ("usb: musb: fail with error when no DMA
controller set"), caused the core platform driver to correctly return an
error code when fail probing.

Unfurtante it also caused bug for a NULL pointer dereference, during
system suspend for the ux500 driver. The reason is a lacking validation
of the corresponding ->driver_data pointer, which won't be set when the
musb core driver fails to probe (or haven't yet been probed).

Fixes: 7d32cdef5356 ("usb: musb: fail with error when no DMA...")
Acked-by: Linus Walleij <linus.walleij@xxxxxxxxxx>
Signed-off-by: Ulf Hansson <ulf.hansson@xxxxxxxxxx>
Signed-off-by: Felipe Balbi <balbi@xxxxxxxxxx>
Signed-off-by: Oliver Neukum <oneukum@xxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/usb/musb/ux500.c |    7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

--- a/drivers/usb/musb/ux500.c
+++ b/drivers/usb/musb/ux500.c
@@ -348,7 +348,9 @@ static int ux500_suspend(struct device *
 	struct ux500_glue	*glue = dev_get_drvdata(dev);
 	struct musb		*musb = glue_to_musb(glue);
 
-	usb_phy_set_suspend(musb->xceiv, 1);
+	if (musb)
+		usb_phy_set_suspend(musb->xceiv, 1);
+
 	clk_disable_unprepare(glue->clk);
 
 	return 0;
@@ -366,7 +368,8 @@ static int ux500_resume(struct device *d
 		return ret;
 	}
 
-	usb_phy_set_suspend(musb->xceiv, 0);
+	if (musb)
+		usb_phy_set_suspend(musb->xceiv, 0);
 
 	return 0;
 }