From: Henry Lin <henryl@xxxxxxxxxx> commit 528699317dd6dc722dccc11b68800cf945109390 upstream. 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> Cc: <stable@xxxxxxxxxxxxxxx> Link: https://lore.kernel.org/r/20191113021420.13377-1-henryl@xxxxxxxxxx Signed-off-by: Takashi Iwai <tiwai@xxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- sound/usb/endpoint.c | 3 +++ 1 file changed, 3 insertions(+) --- a/sound/usb/endpoint.c +++ b/sound/usb/endpoint.c @@ -401,6 +401,9 @@ static void snd_complete_urb(struct 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 */
