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?
Peter
>
> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: Dmitry Osipenko <digetx@xxxxxxxxx>
> ---
> drivers/usb/common/usb-otg-fsm.c | 6 +++++-
> include/linux/usb/otg-fsm.h | 1 +
> 2 files changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/usb/common/usb-otg-fsm.c b/drivers/usb/common/usb-otg-fsm.c
> index 3740cf95560e..0697fde51d00 100644
> --- a/drivers/usb/common/usb-otg-fsm.c
> +++ b/drivers/usb/common/usb-otg-fsm.c
> @@ -193,7 +193,11 @@ static void otg_start_hnp_polling(struct otg_fsm *fsm)
> if (!fsm->host_req_flag)
> return;
>
> - INIT_DELAYED_WORK(&fsm->hnp_polling_work, otg_hnp_polling_work);
> + if (!fsm->hnp_work_inited) {
> + INIT_DELAYED_WORK(&fsm->hnp_polling_work, otg_hnp_polling_work);
> + fsm->hnp_work_inited = true;
> + }
> +
> schedule_delayed_work(&fsm->hnp_polling_work,
> msecs_to_jiffies(T_HOST_REQ_POLL));
> }
> diff --git a/include/linux/usb/otg-fsm.h b/include/linux/usb/otg-fsm.h
> index 3aee78dda16d..784659d4dc99 100644
> --- a/include/linux/usb/otg-fsm.h
> +++ b/include/linux/usb/otg-fsm.h
> @@ -196,6 +196,7 @@ struct otg_fsm {
> struct mutex lock;
> u8 *host_req_flag;
> struct delayed_work hnp_polling_work;
> + bool hnp_work_inited;
> bool state_changed;
> };
>
> --
> 2.30.2
>
--
Thanks,
Peter Chen
