This is a note to let you know that I've just added the patch titled ALSA: hda: hdac_ext_stream: fix potential locking issues to the 5.10-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: alsa-hda-hdac_ext_stream-fix-potential-locking-issues.patch and it can be found in the queue-5.10 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 868ddfcef31ff93ea8961b2e81ea7fe12f6f144b Mon Sep 17 00:00:00 2001 From: Pierre-Louis Bossart <pierre-louis.bossart@xxxxxxxxxxxxxxx> Date: Fri, 24 Sep 2021 14:24:16 -0500 Subject: ALSA: hda: hdac_ext_stream: fix potential locking issues From: Pierre-Louis Bossart <pierre-louis.bossart@xxxxxxxxxxxxxxx> commit 868ddfcef31ff93ea8961b2e81ea7fe12f6f144b upstream. The code for hdac_ext_stream seems inherited from hdac_stream, and similar locking issues are present: the use of the bus->reg_lock spinlock is inconsistent, with only writes to specific fields being protected. Apply similar fix as in hdac_stream by protecting all accesses to 'link_locked' and 'decoupled' fields, with a new helper snd_hdac_ext_stream_decouple_locked() added to simplify code changes. Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@xxxxxxxxxxxxxxx> Link: https://lore.kernel.org/r/20210924192417.169243-4-pierre-louis.bossart@xxxxxxxxxxxxxxx Signed-off-by: Takashi Iwai <tiwai@xxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- include/sound/hdaudio_ext.h | 2 + sound/hda/ext/hdac_ext_stream.c | 46 ++++++++++++++++++++++++---------------- 2 files changed, 30 insertions(+), 18 deletions(-) --- a/include/sound/hdaudio_ext.h +++ b/include/sound/hdaudio_ext.h @@ -88,6 +88,8 @@ struct hdac_ext_stream *snd_hdac_ext_str struct snd_pcm_substream *substream, int type); void snd_hdac_ext_stream_release(struct hdac_ext_stream *azx_dev, int type); +void snd_hdac_ext_stream_decouple_locked(struct hdac_bus *bus, + struct hdac_ext_stream *azx_dev, bool decouple); void snd_hdac_ext_stream_decouple(struct hdac_bus *bus, struct hdac_ext_stream *azx_dev, bool decouple); void snd_hdac_ext_stop_streams(struct hdac_bus *bus); --- a/sound/hda/ext/hdac_ext_stream.c +++ b/sound/hda/ext/hdac_ext_stream.c @@ -106,20 +106,14 @@ void snd_hdac_stream_free_all(struct hda } EXPORT_SYMBOL_GPL(snd_hdac_stream_free_all); -/** - * snd_hdac_ext_stream_decouple - decouple the hdac stream - * @bus: HD-audio core bus - * @stream: HD-audio ext core stream object to initialize - * @decouple: flag to decouple - */ -void snd_hdac_ext_stream_decouple(struct hdac_bus *bus, - struct hdac_ext_stream *stream, bool decouple) +void snd_hdac_ext_stream_decouple_locked(struct hdac_bus *bus, + struct hdac_ext_stream *stream, + bool decouple) { struct hdac_stream *hstream = &stream->hstream; u32 val; int mask = AZX_PPCTL_PROCEN(hstream->index); - spin_lock_irq(&bus->reg_lock); val = readw(bus->ppcap + AZX_REG_PP_PPCTL) & mask; if (decouple && !val) @@ -128,6 +122,20 @@ void snd_hdac_ext_stream_decouple(struct snd_hdac_updatel(bus->ppcap, AZX_REG_PP_PPCTL, mask, 0); stream->decoupled = decouple; +} +EXPORT_SYMBOL_GPL(snd_hdac_ext_stream_decouple_locked); + +/** + * snd_hdac_ext_stream_decouple - decouple the hdac stream + * @bus: HD-audio core bus + * @stream: HD-audio ext core stream object to initialize + * @decouple: flag to decouple + */ +void snd_hdac_ext_stream_decouple(struct hdac_bus *bus, + struct hdac_ext_stream *stream, bool decouple) +{ + spin_lock_irq(&bus->reg_lock); + snd_hdac_ext_stream_decouple_locked(bus, stream, decouple); spin_unlock_irq(&bus->reg_lock); } EXPORT_SYMBOL_GPL(snd_hdac_ext_stream_decouple); @@ -252,6 +260,7 @@ hdac_ext_link_stream_assign(struct hdac_ return NULL; } + spin_lock_irq(&bus->reg_lock); list_for_each_entry(stream, &bus->stream_list, list) { struct hdac_ext_stream *hstream = container_of(stream, struct hdac_ext_stream, @@ -266,17 +275,16 @@ hdac_ext_link_stream_assign(struct hdac_ } if (!hstream->link_locked) { - snd_hdac_ext_stream_decouple(bus, hstream, true); + snd_hdac_ext_stream_decouple_locked(bus, hstream, true); res = hstream; break; } } if (res) { - spin_lock_irq(&bus->reg_lock); res->link_locked = 1; res->link_substream = substream; - spin_unlock_irq(&bus->reg_lock); } + spin_unlock_irq(&bus->reg_lock); return res; } @@ -292,6 +300,7 @@ hdac_ext_host_stream_assign(struct hdac_ return NULL; } + spin_lock_irq(&bus->reg_lock); list_for_each_entry(stream, &bus->stream_list, list) { struct hdac_ext_stream *hstream = container_of(stream, struct hdac_ext_stream, @@ -301,18 +310,17 @@ hdac_ext_host_stream_assign(struct hdac_ if (!stream->opened) { if (!hstream->decoupled) - snd_hdac_ext_stream_decouple(bus, hstream, true); + snd_hdac_ext_stream_decouple_locked(bus, hstream, true); res = hstream; break; } } if (res) { - spin_lock_irq(&bus->reg_lock); res->hstream.opened = 1; res->hstream.running = 0; res->hstream.substream = substream; - spin_unlock_irq(&bus->reg_lock); } + spin_unlock_irq(&bus->reg_lock); return res; } @@ -378,15 +386,17 @@ void snd_hdac_ext_stream_release(struct break; case HDAC_EXT_STREAM_TYPE_HOST: + spin_lock_irq(&bus->reg_lock); if (stream->decoupled && !stream->link_locked) - snd_hdac_ext_stream_decouple(bus, stream, false); + snd_hdac_ext_stream_decouple_locked(bus, stream, false); + spin_unlock_irq(&bus->reg_lock); snd_hdac_stream_release(&stream->hstream); break; case HDAC_EXT_STREAM_TYPE_LINK: - if (stream->decoupled && !stream->hstream.opened) - snd_hdac_ext_stream_decouple(bus, stream, false); spin_lock_irq(&bus->reg_lock); + if (stream->decoupled && !stream->hstream.opened) + snd_hdac_ext_stream_decouple_locked(bus, stream, false); stream->link_locked = 0; stream->link_substream = NULL; spin_unlock_irq(&bus->reg_lock); Patches currently in stable-queue which might be from pierre-louis.bossart@xxxxxxxxxxxxxxx are queue-5.10/alsa-hda-hdac_ext_stream-fix-potential-locking-issues.patch queue-5.10/alsa-hda-hdac_stream-fix-potential-locking-issue-in-snd_hdac_stream_assign.patch queue-5.10/asoc-intel-sof_sdw-add-missing-quirk-for-dell-sku-0a.patch queue-5.10/alsa-intel-dsp-config-add-quirk-for-apl-glk-tgl-devi.patch queue-5.10/asoc-sof-intel-hda-dai-fix-potential-locking-issue.patch