While output urb's snd_complete_urb() is executing, calling
prepare_outbound_urb() may cause endpoint stopped before
prepare_outbound_urb() returns and result in next urb submitted
to stopped endpoint. usb-audio driver cannot re-use it afterwards as
the urb is still hold by usb stack.
This change checks EP_FLAG_RUNNING flag after prepare_outbound_urb() again
to let snd_complete_urb() know the endpoint already stopped and does not
submit next urb. Below kind of error will be fixed:
[ 213.153103] usb 1-2: timeout: still 1 active urbs on EP #1
[ 213.164121] usb 1-2: cannot submit urb 0, error -16: unknown error
Signed-off-by: Henry Lin <henryl@xxxxxxxxxx>
---
sound/usb/endpoint.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/sound/usb/endpoint.c b/sound/usb/endpoint.c
index a2ab8e8d3a93..4a9a2f6ef5a4 100644
--- a/sound/usb/endpoint.c
+++ b/sound/usb/endpoint.c
@@ -388,6 +388,9 @@ static void snd_complete_urb(struct urb *urb)
}
prepare_outbound_urb(ep, ctx);
+ /* can be stopped during prepare callback */
+ if (unlikely(!test_bit(EP_FLAG_RUNNING, &ep->flags)))
+ goto exit_clear;
} else {
retire_inbound_urb(ep, ctx);
/* can be stopped during retire callback */
--
2.17.1
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