Re: [PATCH v1 1/3] Revert "usb: gadget: u_audio: add real feedback implementation"

[Ferry Toth]

Hi,
Op 25-08-2021 om 07:53 schreef Felipe Balbi:
> Ferry Toth <ftoth@xxxxxxxxxxxxxx> writes:
>
> > This reverts commit e89bb4288378b85c82212b60dc98ecda6b3d3a70.
> >
> > The commit is part of a series with commit
> > 24f779dac8f3efb9629adc0e486914d93dc45517 causing a BUG on dwc3
> > hardware, at least on Intel Merrifield platform when configured
> > through configfs:
> > BUG: kernel NULL pointer dereference, address: 0000000000000008
> > ...
> > RIP: 0010:dwc3_gadget_del_and_unmap_request+0x19/0xe0
> > ...
> > Call Trace:
> >   dwc3_remove_requests.constprop.0+0x12f/0x170
> >   __dwc3_gadget_ep_disable+0x7a/0x160
> >   dwc3_gadget_ep_disable+0x3d/0xd0
> >   usb_ep_disable+0x1c/0x70
> >   u_audio_stop_capture+0x79/0x120 [u_audio]
> >   afunc_set_alt+0x73/0x80 [usb_f_uac2]
> >   composite_setup+0x224/0x1b90 [libcomposite]
> >
> > Pavel's suggestion to add
> > `echo "adaptive" > functions/uac2.usb0/c_sync` to the configfs script
> > resolves the issue.
> > Thinh suggests "the crash is probably because of f_uac2 prematurely
> > freeing feedback request before its completion. usb_ep_dequeue() is
> > asynchronous. dwc2() may treat it as a synchronous call so you didn't
> > get a crash."
> >
> > Revert as this is a regression and the kernel shouldn't crash depending
> > on configuration parameters.
> >
> > Reported-by: Ferry Toth <fntoth@xxxxxxxxx>
>
> this should be Signed-off-by ;-)
Indeed. It probably was until I re-worded the commit text.

Will resend tonight v2.