From f8114f8583bb18a467c04ddc1e8978330e445801 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" 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 --- 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 a2cdf3370afe..15d1d5c63c3c 100644 --- a/sound/usb/endpoint.c +++ b/sound/usb/endpoint.c @@ -384,9 +384,6 @@ static void snd_complete_urb(struct urb *urb) if (unlikely(atomic_read(&ep->chip->shutdown))) 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 */ @@ -537,11 +534,6 @@ 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; } @@ -1028,6 +1020,10 @@ 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); } } -- 2.20.1