From c318c81453939e9632535432848013c243fede2e Mon Sep 17 00:00:00 2001 From: Takashi Iwai Date: Wed, 21 Dec 2016 11:28:28 +0100 Subject: [PATCH] Revert "ALSA: usb-audio: Fix race at stopping the stream" [ Upstream commit f8114f8583bb18a467c04ddc1e8978330e445801 ] This reverts commit 16200948d8353fe29a473a394d7d26790deae0e7. The commit was intended to cover the race condition, but it introduced yet another regression for devices with the implicit feedback, leading to a kernel panic due to NULL-dereference in an irq context. As the race condition that was addressed by the commit is very rare and the regression is much worse, let's revert the commit for rc1, and fix the issue properly in a later patch. Fixes: 16200948d835 ("ALSA: usb-audio: Fix race at stopping the stream") Reported-by: Ioan-Adrian Ratiu Cc: Signed-off-by: Takashi Iwai Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin --- sound/usb/endpoint.c | 12 ++++-------- 1 file changed, 4 insertions(+), 8 deletions(-) diff --git a/sound/usb/endpoint.c b/sound/usb/endpoint.c index c43e84b91a2a4..114e3e7ff511d 100644 --- a/sound/usb/endpoint.c +++ b/sound/usb/endpoint.c @@ -357,9 +357,6 @@ static void snd_complete_urb(struct urb *urb) ep->chip->shutdown)) /* device disconnected */ goto exit_clear; - if (unlikely(!test_bit(EP_FLAG_RUNNING, &ep->flags))) - goto exit_clear; - if (usb_pipeout(ep->pipe)) { retire_outbound_urb(ep, ctx); /* can be stopped during retire callback */ @@ -510,11 +507,6 @@ static int wait_clear_urbs(struct snd_usb_endpoint *ep) alive, ep->ep_num); clear_bit(EP_FLAG_STOPPING, &ep->flags); - ep->data_subs = NULL; - ep->sync_slave = NULL; - ep->retire_data_urb = NULL; - ep->prepare_data_urb = NULL; - return 0; } @@ -964,6 +956,10 @@ void snd_usb_endpoint_stop(struct snd_usb_endpoint *ep) if (--ep->use_count == 0) { deactivate_urbs(ep, false); + ep->data_subs = NULL; + ep->sync_slave = NULL; + ep->retire_data_urb = NULL; + ep->prepare_data_urb = NULL; set_bit(EP_FLAG_STOPPING, &ep->flags); } }