Revert "ALSA: usb-audio: Fix race at stopping the stream" (f8114f85) · Commits · 戴 / test

This reverts commit . 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: ("ALSA: usb-audio: Fix race at stopping the stream") Reported-by:

Ioan-Adrian Ratiu <adi@adirat.com> Cc: <stable@vger.kernel.org> Signed-off-by:

Takashi Iwai <tiwai@suse.de> Signed-off-by:

Linus Torvalds <torvalds@linux-foundation.org>

sound/usb/endpoint.c

+4 −8

Original line number	Diff line number	Diff line
		@@ -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);
		}
		}

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