[v2] usb: phy: mxs: Fix NULL pointer dereference on i.MX23/28

[Felipe Balbi <balbi@kernel.org>]

Fabio Estevam <festevam@gmail.com> writes:

> Hi Felipe,
>
> On Mon, Jan 22, 2018 at 10:28 AM, Fabio Estevam <festevam@gmail.com> wrote:
>> Hi Felipe,
>>
>> On Thu, Jan 18, 2018 at 12:22 AM, Fabio Estevam <festevam@gmail.com> wrote:
>>> From: Fabio Estevam <fabio.estevam@nxp.com>
>>>
>>> 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@nxp.com>
>>
>> Could this one be applied to 4.15 final so that we avoid a boot
>> regression on i.MX23/28?
>
> A gentle ping.

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