On Wed 25 Aug 2021 at 22:07, Ferry Toth <fntoth@xxxxxxxxx> wrote:
> Hi,
>
> Op 25-08-2021 om 11:21 schreef Jerome Brunet:
>> When the uac2 function is stopped, there seems to be an issue with some
>> platforms (Intel Merrifield at least)
>>
>> 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]
>>
>> The issue happens only when the gadget is using the sync type "async", not
>> "adaptive". This indicates that problem is likely coming from the feedback
>> endpoint, which is only used with async synchronization mode.
>>
>> Update the feedback endpoint free function to release the endpoint the same
>> way it is done for the data endpoint.
>>
>> Signed-off-by: Jerome Brunet <jbrunet@xxxxxxxxxxxx>
>> ---
>>
>> Hi Ferry,
>>
>> Would you mind trying this before reverting the whole thing ?
>> The HW I have did not show the issue so far so I can't really check
>> if it helps. Hopefully, it does ...
>
> Tested this evening and confirming that this resolves my issue. I can't say
> much about the code itself, maybe Thinh?
>
> Would be great if we could get this in instead of reverting the series.
>
> Tested-by: Ferry Toth <ftoth@xxxxxxxxxxxxxx> (dwc3 / Intel Merrifield)
>
Thanks for reporting and testing this.
I guess we should also add
Reported-by: Ferry Toth <ftoth@xxxxxxxxxxxxxx>
>> drivers/usb/gadget/function/u_audio.c | 15 +++++++++++----
>> 1 file changed, 11 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/usb/gadget/function/u_audio.c b/drivers/usb/gadget/function/u_audio.c
>> index 018dd0978995..63d9340f008e 100644
>> --- a/drivers/usb/gadget/function/u_audio.c
>> +++ b/drivers/usb/gadget/function/u_audio.c
>> @@ -230,7 +230,13 @@ static void u_audio_iso_fback_complete(struct usb_ep *ep,
>> int status = req->status;
>> /* i/f shutting down */
>> - if (!prm->fb_ep_enabled || req->status == -ESHUTDOWN)
>> + if (!prm->fb_ep_enabled) {
>> + kfree(req->buf);
>> + usb_ep_free_request(ep, req);
>> + return;
>> + }
>> +
>> + if (req->status == -ESHUTDOWN)
>> return;
>> /*
>> @@ -421,9 +427,10 @@ static inline void free_ep_fback(struct uac_rtd_params *prm, struct usb_ep *ep)
>> prm->fb_ep_enabled = false;
>> if (prm->req_fback) {
>> - usb_ep_dequeue(ep, prm->req_fback);
>> - kfree(prm->req_fback->buf);
>> - usb_ep_free_request(ep, prm->req_fback);
>> + if (usb_ep_dequeue(ep, prm->req_fback)) {
>> + kfree(prm->req_fback->buf);
>> + usb_ep_free_request(ep, prm->req_fback);
>> + }
>> prm->req_fback = NULL;
>> }
>>
