From ac3467ad7f8734a21b65fa1852316a9b1b8c1fad Mon Sep 17 00:00:00 2001 From: Pierre-Louis Bossart Date: Mon, 19 Sep 2022 14:10:40 +0200 Subject: ALSA: hda: ext: fix locking in stream_release MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The snd_hdac_ext_stream_release() routine uses the bus reg_lock, but releases it before calling snd_hdac_stream_release() where the bus reg_lock is taken again. This creates a timing window where the link stream release could test an invalid 'opened' boolean status and fail to recouple the host and link parts. Fix by exposing a locked version of snd_hdac_stream_release() and use it without releasing the spinlock. Signed-off-by: Pierre-Louis Bossart Reviewed-by: Bard Liao Reviewed-by: Péter Ujfalusi Reviewed-by: Kai Vehmanen Link: https://lore.kernel.org/r/20220919121041.43463-8-pierre-louis.bossart@linux.intel.com Signed-off-by: Takashi Iwai --- sound/hda/ext/hdac_ext_stream.c | 2 +- sound/hda/hdac_stream.c | 19 ++++++++++++++++--- 2 files changed, 17 insertions(+), 4 deletions(-) (limited to 'sound/hda') diff --git a/sound/hda/ext/hdac_ext_stream.c b/sound/hda/ext/hdac_ext_stream.c index 254df9a67bd2..9a2bc7e803dd 100644 --- a/sound/hda/ext/hdac_ext_stream.c +++ b/sound/hda/ext/hdac_ext_stream.c @@ -384,8 +384,8 @@ void snd_hdac_ext_stream_release(struct hdac_ext_stream *hext_stream, int type) spin_lock_irq(&bus->reg_lock); if (hext_stream->decoupled && !hext_stream->link_locked) snd_hdac_ext_stream_decouple_locked(bus, hext_stream, false); + snd_hdac_stream_release_locked(&hext_stream->hstream); spin_unlock_irq(&bus->reg_lock); - snd_hdac_stream_release(&hext_stream->hstream); break; case HDAC_EXT_STREAM_TYPE_LINK: diff --git a/sound/hda/hdac_stream.c b/sound/hda/hdac_stream.c index c056bcc5543d..1b8be39c38a9 100644 --- a/sound/hda/hdac_stream.c +++ b/sound/hda/hdac_stream.c @@ -365,6 +365,21 @@ struct hdac_stream *snd_hdac_stream_assign(struct hdac_bus *bus, } EXPORT_SYMBOL_GPL(snd_hdac_stream_assign); +/** + * snd_hdac_stream_release_locked - release the assigned stream + * @azx_dev: HD-audio core stream to release + * + * Release the stream that has been assigned by snd_hdac_stream_assign(). + * The bus->reg_lock needs to be taken at a higher level + */ +void snd_hdac_stream_release_locked(struct hdac_stream *azx_dev) +{ + azx_dev->opened = 0; + azx_dev->running = 0; + azx_dev->substream = NULL; +} +EXPORT_SYMBOL_GPL(snd_hdac_stream_release_locked); + /** * snd_hdac_stream_release - release the assigned stream * @azx_dev: HD-audio core stream to release @@ -376,9 +391,7 @@ void snd_hdac_stream_release(struct hdac_stream *azx_dev) struct hdac_bus *bus = azx_dev->bus; spin_lock_irq(&bus->reg_lock); - azx_dev->opened = 0; - azx_dev->running = 0; - azx_dev->substream = NULL; + snd_hdac_stream_release_locked(azx_dev); spin_unlock_irq(&bus->reg_lock); } EXPORT_SYMBOL_GPL(snd_hdac_stream_release); -- cgit