> Commit e93650994a95 ("usb: phy: mxs: add usb charger type detection") causes the
> following kernel hang on i.MX28:
>
> [ 2.207973] usbcore: registered new interface driver usb-storage
> [ 2.235659] Unable to handle kernel NULL pointer dereference at virtual address
> 00000188
> [ 2.244195] pgd = (ptrval)
> [ 2.246994] [00000188] *pgd=00000000
> [ 2.250676] Internal error: Oops: 5 [#1] ARM
> [ 2.254979] Modules linked in:
> [ 2.258089] CPU: 0 PID: 1 Comm: swapper Not tainted 4.15.0-rc8-next-20180117-
> 00002-g75d5f21 #7
> [ 2.266724] Hardware name: Freescale MXS (Device Tree)
> [ 2.271921] PC is at regmap_read+0x0/0x5c
> [ 2.275977] LR is at mxs_phy_charger_detect+0x34/0x1dc
>
> mxs_phy_charger_detect() makes accesses to the anatop registers via regmap,
> however i.MX23/28 do not have such registers, which causes a NULL pointer
> dereference.
>
> Fix the issue by doing a NULL check on the 'regmap' pointer.
>
> Fixes: e93650994a95 ("usb: phy: mxs: add usb charger type detection")
> Signed-off-by: Fabio Estevam <fabio.estevam@xxxxxxx>
> ---
> Changes since v1:
> - Perform a NULL check on regmap (Jun Li)
>
> drivers/usb/phy/phy-mxs-usb.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/drivers/usb/phy/phy-mxs-usb.c b/drivers/usb/phy/phy-mxs-usb.c index
> da031c4..4e2eb9d 100644
> --- a/drivers/usb/phy/phy-mxs-usb.c
> +++ b/drivers/usb/phy/phy-mxs-usb.c
> @@ -602,6 +602,9 @@ static enum usb_charger_type
> mxs_phy_charger_detect(struct usb_phy *phy)
> void __iomem *base = phy->io_priv;
> enum usb_charger_type chgr_type = UNKNOWN_TYPE;
>
> + if (!regmap)
> + return UNKNOWN_TYPE;
> +
> if (mxs_charger_data_contact_detect(mxs_phy))
> return chgr_type;
Acked-by: Peter Chen <peter.chen@xxxxxxx>
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