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.
Unable to handle kernel NULL pointer dereference at virtual address 00000126)
...
PC is at __run_timers.part.0+0x150/0x228
LR is at __next_timer_interrupt+0x51/0x9c
...
(__run_timers.part.0) from [<c0187a2b>] (run_timer_softirq+0x2f/0x50)
(run_timer_softirq) from [<c01013ad>] (__do_softirq+0xd5/0x2f0)
(__do_softirq) from [<c012589b>] (irq_exit+0xab/0xb8)
(irq_exit) from [<c0170341>] (handle_domain_irq+0x45/0x60)
(handle_domain_irq) from [<c04c4a43>] (gic_handle_irq+0x6b/0x7c)
(gic_handle_irq) from [<c0100b65>] (__irq_svc+0x65/0xac)
Cc: stable@xxxxxxxxxxxxxxx
Acked-by: Peter Chen <peter.chen@xxxxxxxxxx>
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;
};
--
2.32.0
