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SubjectRe: [PATCH v6] usb: gadget: udc: renesas_usb3: Fix use after free bug in renesas_usb3_remove due to race condition
Greg KH <gregkh@linuxfoundation.org> 于2023年3月17日周五 02:09写道:
>
> On Fri, Mar 17, 2023 at 01:54:57AM +0800, Zheng Wang wrote:
> > In renesas_usb3_probe, role_work is bound with renesas_usb3_role_work.
> > renesas_usb3_start will be called to start the work.
> >
> > If we remove the driver which will call usbhs_remove, there may be
> > an unfinished work. The possible sequence is as follows:
> >
> > Fix it by canceling the work before cleanup in the renesas_usb3_remove.
> >
> > Note that removing a driver is a root-only operation, and should never
> > happen.
> >
> > CPU0 CPU1
> >
> > | renesas_usb3_role_work
> > renesas_usb3_remove |
> > usb_role_switch_unregister|
> > device_unregister |
> > kfree(sw) |
> > free usb3->role_sw |
> > | usb_role_switch_set_role
> > | //use usb3->role_sw
>
> Please use spaces for this, as something went wrong and it does not line
> up :(

Oh yes, will do in the next version. Thanks for your advice :)

Best regards,
Zheng

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