This is a note to let you know that I've just added the patch titled media: usbtv: Fix deadlock on suspend to the 4.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: media-usbtv-fix-deadlock-on-suspend.patch and it can be found in the queue-4.14 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 8a7e27fd5cd696ba564a3f62cedef7269cfd0723 Mon Sep 17 00:00:00 2001 From: Maxim Mikityanskiy <maxtram95@xxxxxxxxx> Date: Fri, 5 Feb 2021 23:51:39 +0100 Subject: media: usbtv: Fix deadlock on suspend From: Maxim Mikityanskiy <maxtram95@xxxxxxxxx> 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: 63ddf68de52e ("[media] usbtv: add audio support") Signed-off-by: Maxim Mikityanskiy <maxtram95@xxxxxxxxx> Signed-off-by: Hans Verkuil <hverkuil-cisco@xxxxxxxxx> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/media/usb/usbtv/usbtv-audio.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/drivers/media/usb/usbtv/usbtv-audio.c +++ b/drivers/media/usb/usbtv/usbtv-audio.c @@ -398,7 +398,7 @@ void usbtv_audio_free(struct usbtv *usbt 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; } } Patches currently in stable-queue which might be from maxtram95@xxxxxxxxx are queue-4.14/media-usbtv-fix-deadlock-on-suspend.patch