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Commit 8ebbf254 authored by Maxim Mikityanskiy's avatar Maxim Mikityanskiy Committed by Greg Kroah-Hartman
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media: usbtv: Fix deadlock on suspend 



commit 8a7e27fd5cd696ba564a3f62cedef7269cfd0723 upstream.

usbtv doesn't support power management, so on system suspend the
.disconnect callback of the driver is called. The teardown sequence
includes a call to snd_card_free. Its implementation waits until the
refcount of the sound card device drops to zero, however, if its file is
open, snd_card_file_add takes a reference, which can't be dropped during
the suspend, because the userspace processes are already frozen at this
point. snd_card_free waits for completion forever, leading to a hang on
suspend.

This commit fixes this deadlock condition by replacing snd_card_free
with snd_card_free_when_closed, that doesn't wait until all references
are released, allowing suspend to progress.

Fixes: 63ddf68d ("[media] usbtv: add audio support")
Signed-off-by: default avatarMaxim Mikityanskiy <maxtram95@gmail.com>
Signed-off-by: default avatarHans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 92c476c8

drivers/media/usb/usbtv/usbtv-audio.c

+1 −1
Original line number Diff line number Diff line
@@ -399,7 +399,7 @@ void usbtv_audio_free(struct usbtv *usbtv) 
	cancel_work_sync(&usbtv->snd_trigger);



	if (usbtv->snd && usbtv->udev) {

		snd_card_free(usbtv->snd);

		snd_card_free_when_closed(usbtv->snd);

		usbtv->snd = NULL;

	}

}