Hi Heikki,
> Subject: Re: [PATCH v2] usb: typec: hd3ss3220: Fix NULL pointer crash
>
> Hi Biju,
>
> On Fri, Dec 09, 2022 at 05:07:40PM +0000, Biju Das wrote:
> > The value returned by usb_role_switch_get() can be NULL and it leads
> > to NULL pointer crash. This patch fixes this issue by adding NULL
> > check for the role switch handle.
> >
> > [ 25.336613] Hardware name: Silicon Linux RZ/G2E evaluation kit EK874
> (CAT874 + CAT875) (DT)
> > [ 25.344991] Workqueue: events_unbound deferred_probe_work_func
> > [ 25.350869] pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS
> BTYPE=--)
> > [ 25.357854] pc : renesas_usb3_role_switch_get+0x40/0x80
> [renesas_usb3]
> > [ 25.364428] lr : renesas_usb3_role_switch_get+0x24/0x80
> [renesas_usb3]
> > [ 25.370986] sp : ffff80000a4b3a40
> > [ 25.374311] x29: ffff80000a4b3a40 x28: 0000000000000000 x27:
> 0000000000000000
> > [ 25.381476] x26: ffff80000a3ade78 x25: ffff00000a809005 x24:
> ffff80000117f178
> > [ 25.388641] x23: ffff00000a8d7810 x22: ffff00000a8d8410 x21:
> 0000000000000000
> > [ 25.395805] x20: ffff000011cd7080 x19: ffff000011cd7080 x18:
> 0000000000000020
> > [ 25.402969] x17: ffff800076196000 x16: ffff800008004000 x15:
> 0000000000004000
> > [ 25.410133] x14: 000000000000022b x13: 0000000000000001 x12:
> 0000000000000001
> > [ 25.417291] x11: 0000000000000000 x10: 0000000000000a40 x9 :
> ffff80000a4b3770
> > [ 25.424452] x8 : ffff00007fbc9000 x7 : 0040000000000008 x6 :
> ffff00000a8d8590
> > [ 25.431615] x5 : ffff80000a4b3960 x4 : 0000000000000000 x3 :
> ffff00000a8d84f4
> > [ 25.438776] x2 : 0000000000000218 x1 : ffff80000a715218 x0 :
> 0000000000000218
> > [ 25.445942] Call trace:
> > [ 25.448398] renesas_usb3_role_switch_get+0x40/0x80 [renesas_usb3]
> > [ 25.454613] renesas_usb3_role_switch_set+0x4c/0x440 [renesas_usb3]
> > [ 25.460908] usb_role_switch_set_role+0x44/0xa4
> > [ 25.465468] hd3ss3220_set_role+0xa0/0x100 [hd3ss3220]
> > [ 25.470635] hd3ss3220_probe+0x118/0x2fc [hd3ss3220]
> > [ 25.475621] i2c_device_probe+0x338/0x384
>
> Based on that backtrace, your role switch is not NULL.
>
> You can only end up calling renesas_usb3_role_switch_set() if your
> hd3ss3220->role_sw contains a handle to the renesas usb3 role switch.
Looks you are correct.
>
> > Fixes: 5a9a8a4c5058 ("usb: typec: hd3ss3220: hd3ss3220_probe() warn:
> > passing zero to 'PTR_ERR'")
> > Cc: stable@xxxxxxxxxxxxxxx
> > Signed-off-by: Biju Das <biju.das.jz@xxxxxxxxxxxxxx>
> > ---
> > This issue triggered on RZ/G2E board, where there is no USB3 firmware
> > and it returned a null role switch handle.
> >
> > v1->v2:
> > * Make it as individual patch
> > * Added Cc tag
> > ---
> > drivers/usb/typec/hd3ss3220.c | 5 ++++-
> > 1 file changed, 4 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/usb/typec/hd3ss3220.c
> > b/drivers/usb/typec/hd3ss3220.c index 2a58185fb14c..c24bbccd14f9
> > 100644
> > --- a/drivers/usb/typec/hd3ss3220.c
> > +++ b/drivers/usb/typec/hd3ss3220.c
> > @@ -186,7 +186,10 @@ static int hd3ss3220_probe(struct i2c_client
> *client,
> > hd3ss3220->role_sw = usb_role_switch_get(hd3ss3220->dev);
> > }
> >
> > - if (IS_ERR(hd3ss3220->role_sw)) {
> > + if (!hd3ss3220->role_sw) {
> > + ret = -ENODEV;
> > + goto err_put_fwnode;
> > + } else if (IS_ERR(hd3ss3220->role_sw)) {
> > ret = PTR_ERR(hd3ss3220->role_sw);
> > goto err_put_fwnode;
> > }
>
> You should not do that.
>
> Either I'm missing something, or this patch is hiding some other issue.
Looks It is a bug in renesas_usb3.c rather than this driver.
But how we will prevent hd3ss3220_set_role being called after
usb_role_switch_unregister(usb3->role_sw) from renesas_usb3.c
driver??
Cheers,
Biju
