[PATCH v3] usb: chipidea: ci_hdrc_imx: Also search for 'phys' phandle

Fabio Estevam
2021-09-21T11:38:11Z

When passing 'phys' in the devicetree to describe the USB PHY phandle
(which is the recommended way according to
Documentation/devicetree/bindings/usb/ci-hdrc-usb2.txt) the
following NULL pointer dereference is observed on i.MX7 and i.MX8MM:

[ 1.489344] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000098
[ 1.498170] Mem abort info:
[ 1.500966] ESR = 0x96000044
[ 1.504030] EC = 0x25: DABT (current EL), IL = 32 bits
[ 1.509356] SET = 0, FnV = 0
[ 1.512416] EA = 0, S1PTW = 0
[ 1.515569] FSC = 0x04: level 0 translation fault
[ 1.520458] Data abort info:
[ 1.523349] ISV = 0, ISS = 0x00000044
[ 1.527196] CM = 0, WnR = 1
[ 1.530176] [0000000000000098] user address but active_mm is swapper
[ 1.536544] Internal error: Oops: 96000044 [#1] PREEMPT SMP
[ 1.542125] Modules linked in:
[ 1.545190] CPU: 3 PID: 7 Comm: kworker/u8:0 Not tainted 5.14.0-dirty #3
[ 1.551901] Hardware name: Kontron i.MX8MM N801X S (DT)
[ 1.557133] Workqueue: events_unbound deferred_probe_work_func
[ 1.562984] pstate: 80000005 (Nzcv daif -PAN -UAO -TCO BTYPE=--)
[ 1.568998] pc : imx7d_charger_detection+0x3f0/0x510
[ 1.573973] lr : imx7d_charger_detection+0x22c/0x510

This happens because the charger functions check for the phy presence
inside the imx_usbmisc_data structure (data->usb_phy), but the chipidea
core populates the usb_phy passed via 'phys' inside 'struct ci_hdrc'
(ci->usb_phy) instead.

This causes the NULL pointer dereference inside imx7d_charger_detection().

Fix it by also searching for 'phys' in case 'fsl,usbphy' is not found.

Tested on a imx7s-warp board.

Cc: stable@vger.kernel.org
Fixes: 746f316b753a ("usb: chipidea: introduce imx7d USB charger detection")
Reported-by: Heiko Thiery <heiko.thiery@gmail.com>
Signed-off-by: Fabio Estevam <festevam@gmail.com>
Reviewed-by: Frieder Schrempf <frieder.schrempf@kontron.de>
---
Changes since v2:

- Added Frieder's reviewed-by tag.
- Cc stable
- Improved the commit log and fixed typo in 'dereferenced'

drivers/usb/chipidea/ci_hdrc_imx.c | 15 ++++++++++-----
1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/drivers/usb/chipidea/ci_hdrc_imx.c b/drivers/usb/chipidea/ci_hdrc_imx.c
index 8b7bc10b6e8b..f1d100671ee6 100644
--- a/drivers/usb/chipidea/ci_hdrc_imx.c
+++ b/drivers/usb/chipidea/ci_hdrc_imx.c
@@ -420,11 +420,16 @@ static int ci_hdrc_imx_probe(struct platform_device *pdev)
data->phy = devm_usb_get_phy_by_phandle(dev, "fsl,usbphy", 0);
if (IS_ERR(data->phy)) {
ret = PTR_ERR(data->phy);
- /* Return -EINVAL if no usbphy is available */
- if (ret == -ENODEV)
- data->phy = NULL;
- else
- goto err_clk;
+ if (ret == -ENODEV) {
+ data->phy = devm_usb_get_phy_by_phandle(dev, "phys", 0);
+ if (IS_ERR(data->phy)) {
+ ret = PTR_ERR(data->phy);
+ if (ret == -ENODEV)
+ data->phy = NULL;
+ else
+ goto err_clk;
+ }
+ }
}

pdata.usb_phy = data->phy;
--
2.25.1