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Subject[PATCH v3 05/12] usb: otg-fsm: Fix hrtimer list corruption
Date
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.

Cc: stable@vger.kernel.org
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
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
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