This is a note to let you know that I've just added the patch titled
ALSA: hda: hdac_stream: fix potential locking issue in snd_hdac_stream_assign()
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_stream-fix-potential-locking-issue-in-snd_hdac_stream_assign.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 1465d06a6d8580e73ae65f8590392df58c5ed2fd Mon Sep 17 00:00:00 2001
From: Pierre-Louis Bossart <pierre-louis.bossart@xxxxxxxxxxxxxxx>
Date: Fri, 24 Sep 2021 14:24:14 -0500
Subject: ALSA: hda: hdac_stream: fix potential locking issue in snd_hdac_stream_assign()
From: Pierre-Louis Bossart <pierre-louis.bossart@xxxxxxxxxxxxxxx>
commit 1465d06a6d8580e73ae65f8590392df58c5ed2fd upstream.
The fields 'opened', 'running', 'assigned_key' are all protected by a
spinlock, but the spinlock is not taken when looking for a
stream. This can result in a possible race between assign() and
release().
Fix by taking the spinlock before walking through the bus stream list.
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@xxxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20210924192417.169243-2-pierre-louis.bossart@xxxxxxxxxxxxxxx
Signed-off-by: Takashi Iwai <tiwai@xxxxxxx>
Cc: Scott Bruce <smbruce@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
sound/hda/hdac_stream.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
--- a/sound/hda/hdac_stream.c
+++ b/sound/hda/hdac_stream.c
@@ -296,6 +296,7 @@ struct hdac_stream *snd_hdac_stream_assi
int key = (substream->pcm->device << 16) | (substream->number << 2) |
(substream->stream + 1);
+ spin_lock_irq(&bus->reg_lock);
list_for_each_entry(azx_dev, &bus->stream_list, list) {
if (azx_dev->direction != substream->stream)
continue;
@@ -309,13 +310,12 @@ struct hdac_stream *snd_hdac_stream_assi
res = azx_dev;
}
if (res) {
- spin_lock_irq(&bus->reg_lock);
res->opened = 1;
res->running = 0;
res->assigned_key = key;
res->substream = substream;
- spin_unlock_irq(&bus->reg_lock);
}
+ spin_unlock_irq(&bus->reg_lock);
return res;
}
EXPORT_SYMBOL_GPL(snd_hdac_stream_assign);
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
