On Do, 2018-06-14 at 18:36 +0200, Sebastian Andrzej Siewior wrote:
> In the code path
> __usb_hcd_giveback_urb()
> -> wdm_in_callback()
> -> service_outstanding_interrupt()
>
> The function service_outstanding_interrupt() will unconditionally enable
> interrupts during unlock and invoke usb_submit_urb() with GFP_KERNEL.
> If the HCD completes in BH (like ehci does) then the context remains
> atomic due local_bh_disable() and enabling interrupts does not change
> this.
>
> Defer the error case handling to a workqueue as suggested by Oliver
> Neukum. In case of an error the worker performs the read out and wakes
> the user.
>
> Fixes: c1da59dad0eb ("cdc-wdm: Clear read pipeline in case of error")
> Cc: Robert Foss <robert.foss@xxxxxxxxxxxxx>
> Cc: Oliver Neukum <oneukum@xxxxxxxx>
> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
<Acked-by: Oliver Neukum <oneukum@xxxxxxxx>
It fixes the identified issue.
Regards
Oliver
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