From 22b3cc0f63ab394d7828e8d1cbdc81382408c8c9 Mon Sep 17 00:00:00 2001 From: Dmitry Osipenko Date: Sat, 17 Jul 2021 21:21:27 +0300 Subject: [PATCH] usb: otg-fsm: Fix hrtimer list corruption commit bf88fef0b6f1488abeca594d377991171c00e52a upstream. 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 [] (run_timer_softirq+0x2f/0x50) (run_timer_softirq) from [] (__do_softirq+0xd5/0x2f0) (__do_softirq) from [] (irq_exit+0xab/0xb8) (irq_exit) from [] (handle_domain_irq+0x45/0x60) (handle_domain_irq) from [] (gic_handle_irq+0x6b/0x7c) (gic_handle_irq) from [] (__irq_svc+0x65/0xac) Cc: stable@vger.kernel.org Acked-by: Peter Chen Signed-off-by: Dmitry Osipenko Link: https://lore.kernel.org/r/20210717182134.30262-6-digetx@gmail.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Greg Kroah-Hartman --- 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 2f537bbdda09..362cca983e6e 100644 --- a/drivers/usb/common/usb-otg-fsm.c +++ b/drivers/usb/common/usb-otg-fsm.c @@ -199,7 +199,11 @@ 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 7a0350535cb1..603b298dc747 100644 --- a/include/linux/usb/otg-fsm.h +++ b/include/linux/usb/otg-fsm.h @@ -210,6 +210,7 @@ struct otg_fsm { struct mutex lock; u8 *host_req_flag; struct delayed_work hnp_polling_work; + bool hnp_work_inited; bool state_changed; }; -- 2.20.1