Hi,
Jack Pham <jackp@xxxxxxxxxxxxxx> writes:
> Will try to take a stab at this...
>
> On Tue, Oct 29, 2019 at 01:30:23PM +0200, Roger Quadros wrote:
>> irq/170-dwc3-1240 [000] d... 85.449686: dwc3_event: event (0000c040): ep0out: Transfer Complete (sIL) [Setup Phase]
>> irq/170-dwc3-1240 [000] d... 85.449688: dwc3_ctrl_req: Set Interface(Intf = 1, Alt.Setting = 0)
>> irq/170-dwc3-1240 [000] d... 85.449693: dwc3_ep_dequeue: ep1out: req ee75d6ac length 0/256 zsI ==> -115
>> irq/170-dwc3-1240 [000] d... 85.449697: dwc3_gadget_ep_cmd: ep1out: cmd 'End Transfer' [20d08] params 00000000 00000000 00000000 --> status: Successful
>> irq/170-dwc3-1240 [000] d... 85.449799: dwc3_free_request: ep1out: req ee75d6ac length 0/256 zsI ==> -115
>
> req ee75d6ac is dequeued by f_uac2, and immediately freed. There is no
> giveback here, but oddly the givebacks happen at the end of the log
> right before the panic.
>
>> irq/170-dwc3-1240 [000] d... 85.449800: dwc3_ep_dequeue: ep1out: req c26c10a3 length 0/256 zsI ==> -115
>> irq/170-dwc3-1240 [000] d... 85.449803: dwc3_gadget_ep_cmd: ep1out: cmd 'End Transfer' [d08] params 00000000 00000000 00000000 --> status: Successful
>> irq/170-dwc3-1240 [000] d... 85.449905: dwc3_free_request: ep1out: req c26c10a3 length 0/256 zsI ==> -115
>
> ditto for req c26c10a3
>
>> irq/170-dwc3-1240 [000] d... 85.449906: dwc3_gadget_ep_disable: ep1out: mps 256/1024 streams 15 burst 0 ring 3/1 flags E:swBp:>
>> irq/170-dwc3-1240 [000] d... 85.449909: dwc3_gadget_ep_cmd: ep1out: cmd 'End Transfer' [c08] params 00000000 00000000 00000000 --> status: Successful
>
> Finally usb_ep_disable() is called on ep1out.
>
>> irq/170-dwc3-1240 [000] d... 85.450013: dwc3_event: event (000020c2): ep0in: [Status Phase]
>> irq/170-dwc3-1240 [000] d... 85.450013: dwc3_prepare_trb: ep0in: trb 089fca0d buf 00000000fe05b000 size 0 ctrl 00000c33 (HLcs:SC:status2)
>> irq/170-dwc3-1240 [000] d... 85.450019: dwc3_gadget_ep_cmd: ep0in: cmd 'Start Transfer' [406] params 00000000 fe05b000 00000000 --> status: Successful
>> irq/170-dwc3-1240 [000] d... 85.450026: dwc3_event: event (080201c4): ep1out: Endpoint Command Complete
>> irq/170-dwc3-1240 [000] d... 85.450027: dwc3_event: event (080001c4): ep1out: Endpoint Command Complete
>
> Completions for the two End Transfer commands sent during ep_dequeue().
>
>> irq/170-dwc3-1240 [000] d... 85.450043: dwc3_event: event (0000c042): ep0in: Transfer Complete (sIL) [Status Phase]
>> irq/170-dwc3-1240 [000] d... 85.450044: dwc3_complete_trb: ep0out: trb 089fca0d buf 00000000fe05b000 size 0 ctrl 00000c32 (hLcs:SC:status2)
>> irq/170-dwc3-1240 [000] d... 85.450047: dwc3_gadget_giveback: ep0out: req 36600525 length 0/0 zsI ==> 0
>> irq/170-dwc3-1240 [000] d... 85.450049: dwc3_prepare_trb: ep0out: trb 089fca0d buf 00000000fe05b000 size 8 ctrl 00000c23 (HLcs:SC:setup)
>> irq/170-dwc3-1240 [000] d... 85.450055: dwc3_gadget_ep_cmd: ep0out: cmd 'Start Transfer' [406] params 00000000 fe05b000 00000000 --> status: Successful
>> irq/170-dwc3-1240 [000] d... 85.450547: dwc3_event: event (0000c040): ep0out: Transfer Complete (sIL) [Setup Phase]
>> irq/170-dwc3-1240 [000] d... 85.450550: dwc3_ctrl_req: Set Interface(Intf = 2, Alt.Setting = 0)
>> irq/170-dwc3-1240 [000] d... 85.450555: dwc3_ep_dequeue: ep1in: req f11a91c0 length 0/192 zsI ==> -115
>> irq/170-dwc3-1240 [000] d... 85.450556: dwc3_gadget_giveback: ep1in: req f11a91c0 length 0/192 zsI ==> -104
>> irq/170-dwc3-1240 [000] d... 85.450557: dwc3_free_request: ep1in: req f11a91c0 length 0/192 zsI ==> -104
>> irq/170-dwc3-1240 [000] d... 85.450559: dwc3_ep_dequeue: ep1in: req d9b92dec length 0/192 zsI ==> -115
>> irq/170-dwc3-1240 [000] d... 85.450560: dwc3_gadget_giveback: ep1in: req d9b92dec length 0/192 zsI ==> -104
>> irq/170-dwc3-1240 [000] d... 85.450561: dwc3_free_request: ep1in: req d9b92dec length 0/192 zsI ==> -104
>> irq/170-dwc3-1240 [000] d... 85.450562: dwc3_gadget_ep_disable: ep1in: mps 192/1024 streams 15 burst 0 ring 0/0 flags E:swbp:<
>> irq/170-dwc3-1240 [000] d... 85.450564: dwc3_gadget_giveback: ep1out: req ee75d6ac length 0/256 zsI ==> -108
>> irq/170-dwc3-1240 [000] d... 85.450566: dwc3_gadget_giveback: ep1out: req c26c10a3 length 0/256 zsI ==> -108
>> irq/170-dwc3-1240 [000] d... 85.450567: dwc3_gadget_giveback: : req d4301893 length 0/0 zsI ==> 0
>
> Giveback happens on above two reqs after they are already freed. Could
> it be due to f_uac2 / u_audio.c performing usb_ep_free_request()
> immediately after usb_ep_dequeue() without waiting for completion?
this could be a race condition. Add a trace_printk() at the cancelation,
see if the request is moved to cancelled list.
diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index 86dc1db788a9..affc2f7a929d 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -1513,6 +1513,7 @@ static void dwc3_gadget_ep_cleanup_cancelled_requests(struct dwc3_ep *dep)
struct dwc3_request *tmp;
list_for_each_entry_safe(req, tmp, &dep->cancelled_list, list) {
+ trace_printk("---> completing cancellation of req %p\n", req);
dwc3_gadget_ep_skip_trbs(dep, req);
dwc3_gadget_giveback(dep, req, -ECONNRESET);
}
@@ -1551,6 +1552,7 @@ static int dwc3_gadget_ep_dequeue(struct usb_ep *ep,
if (!r->trb)
goto out0;
+ trace_printk("---> req %p moved to cancelled\n", req);
dwc3_gadget_move_cancelled_request(req);
if (dep->flags & DWC3_EP_TRANSFER_STARTED)
goto out0;
--
balbi
