From: Maxim Mikityanskiy Date: Fri, 5 Feb 2021 22:51:39 +0000 (+0100) Subject: media: usbtv: Fix deadlock on suspend X-Git-Tag: v4.14.226~65 X-Git-Url: https://git.fsl.cs.sunysb.edu/?a=commitdiff_plain;h=f197ef408f31db886cab97ad83a086210fd6db13;p=wrapfs-5.3.y.git 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: 63ddf68de52e ("[media] usbtv: add audio support") Signed-off-by: Maxim Mikityanskiy Signed-off-by: Hans Verkuil Signed-off-by: Mauro Carvalho Chehab Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/media/usb/usbtv/usbtv-audio.c b/drivers/media/usb/usbtv/usbtv-audio.c index 2c2ca77fa01f..10d9eded6319 100644 --- 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 *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; } }