When the uac2 function is stopped, there seems to be an issue reported on
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 coming from the feedback
endpoint, which is only used with async synchronization mode.
The problem is that request is freed regardless of usb_ep_dequeue(), which
ends up badly if the request is not actually dequeued yet.
Update the feedback endpoint free function to release the endpoint the same
way it is done for the data endpoint, which takes care of the problem.
Reported-by: Ferry Toth <[email protected]>
Tested-by: Ferry Toth <[email protected]>
Signed-off-by: Jerome Brunet <[email protected]>
---
Hi Felipe,
This solves the issue reported here [0] and makes revert [1]
unnecessary.
[0]: https://lore.kernel.org/r/[email protected]
[1]: https://lore.kernel.org/r/[email protected]
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;
}
--
2.33.0
Hi,
Jerome Brunet <[email protected]> writes:
> When the uac2 function is stopped, there seems to be an issue reported on
> 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 coming from the feedback
> endpoint, which is only used with async synchronization mode.
>
> The problem is that request is freed regardless of usb_ep_dequeue(), which
> ends up badly if the request is not actually dequeued yet.
>
> Update the feedback endpoint free function to release the endpoint the same
> way it is done for the data endpoint, which takes care of the problem.
>
> Reported-by: Ferry Toth <[email protected]>
> Tested-by: Ferry Toth <[email protected]>
> Signed-off-by: Jerome Brunet <[email protected]>
> ---
> Hi Felipe,
>
> This solves the issue reported here [0] and makes revert [1]
> unnecessary.
awesome work! Thanks
Acked-by: Felipe Balbi <[email protected]>
--
balbi
On Fri 27 Aug 2021 at 11:05, Felipe Balbi <[email protected]> wrote:
> Hi,
>
> Jerome Brunet <[email protected]> writes:
>
>> When the uac2 function is stopped, there seems to be an issue reported on
>> 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 coming from the feedback
>> endpoint, which is only used with async synchronization mode.
>>
>> The problem is that request is freed regardless of usb_ep_dequeue(), which
>> ends up badly if the request is not actually dequeued yet.
>>
>> Update the feedback endpoint free function to release the endpoint the same
>> way it is done for the data endpoint, which takes care of the problem.
>>
>> Reported-by: Ferry Toth <[email protected]>
>> Tested-by: Ferry Toth <[email protected]>
>> Signed-off-by: Jerome Brunet <[email protected]>
>> ---
>> Hi Felipe,
>>
>> This solves the issue reported here [0] and makes revert [1]
>> unnecessary.
>
> awesome work! Thanks
>
> Acked-by: Felipe Balbi <[email protected]>
Forgot the fixes tag
Fixes: 24f779dac8f3 ("usb: gadget: f_uac2/u_audio: add feedback endpoint support")