Re: [PATCH v2 05/12] usb: otg-fsm: Fix hrtimer list corruption
From: Peter Chen
Date: Sun Jul 04 2021 - 22:22:03 EST
On 21-07-03 20:22:38, Dmitry Osipenko wrote:
> 03.07.2021 14:08, Peter Chen пишет:
> > On 21-07-02 02:43:10, Dmitry Osipenko wrote:
> >> The HNP work can be re-scheduled while it's still in-fly. This results in
> >> re-initialization of the busy work, resetting the hrtimer's list node of
> >> the work and crashing kernel with null dereference within kernel/timer
> >> once work's timer is expired. It's very easy to trigger this problem by
> >> re-plugging USB cable quickly. Initialize HNP work only once to fix this
> >> trouble.
> > Fully OTG compliance support has not maintained for years, what's the use case you
> > still want to use?
> I don't have any use case for it, but I had CONFIG_USB_OTG_FSM=y and it
> was crashing kernel badly. The OTG works perfectly fine without the FSM.
You could add below at your dts to disable OTG FSM:
Since there are no users for OTG FSM, it hasn't maintained for years,
I am not sure if it still works OK. If I remember correctly, the VBUS
will be off if you enable HNP, and the device at the host port will be
disconnected, that's may not your expectation.