This is a note to let you know that I've just added the patch titled
media: usbtv: Fix deadlock on suspend
to the 5.11-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-5.11 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
@@ -371,7 +371,7 @@ 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-5.11/media-usbtv-fix-deadlock-on-suspend.patch
