Re: [PATCH v2 05/12] usb: otg-fsm: Fix hrtimer list corruption
From: Dmitry Osipenko <digetx@gmail.com>
Date: 2021-07-05 02:45:15
Also in:
linux-pm, linux-tegra, linux-usb, lkml
05.07.2021 05:21, Peter Chen пишет:
On 21-07-03 20:22:38, Dmitry Osipenko wrote:quoted
03.07.2021 14:08, Peter Chen пишет:quoted
On 21-07-02 02:43:10, Dmitry Osipenko wrote:quoted
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: hnp-disable srp-disable adp-disable 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.
Since OTG FSM is known to be in a bad shape, could you please make a patch to remove it? I hope it's not enabled by default in a distro kernels.. oh no, CONFIG_USB_OTG_FSM=y at least in ArchLinux [1]. [1] https://archlinuxarm.org/packages/armv7h/linux-armv7/files/config I think we should fix that hrtimer bug, beackport the fix into stable kernels and then remove OTG FSM. Does this sound good to you?