This is a note to let you know that I've just added the patch titled
ALSA: jack: Fix mutex call in snd_jack_report()
to the 6.4-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-jack-fix-mutex-call-in-snd_jack_report.patch
and it can be found in the queue-6.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 89dbb335cb6a627a4067bc42caa09c8bc3326d40 Mon Sep 17 00:00:00 2001
From: Takashi Iwai <tiwai@xxxxxxx>
Date: Thu, 6 Jul 2023 17:53:57 +0200
Subject: ALSA: jack: Fix mutex call in snd_jack_report()
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From: Takashi Iwai <tiwai@xxxxxxx>
commit 89dbb335cb6a627a4067bc42caa09c8bc3326d40 upstream.
snd_jack_report() is supposed to be callable from an IRQ context, too,
and it's indeed used in that way from virtsnd driver. The fix for
input_dev race in commit 1b6a6fc5280e ("ALSA: jack: Access input_dev
under mutex"), however, introduced a mutex lock in snd_jack_report(),
and this resulted in a potential sleep-in-atomic.
For addressing that problem, this patch changes the relevant code to
use the object get/put and removes the mutex usage. That is,
snd_jack_report(), it takes input_get_device() and leaves with
input_put_device() for assuring the input_dev being assigned.
Although the whole mutex could be reduced, we keep it because it can
be still a protection for potential races between creation and
deletion.
Fixes: 1b6a6fc5280e ("ALSA: jack: Access input_dev under mutex")
Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Closes: https://lore.kernel.org/r/cf95f7fe-a748-4990-8378-000491b40329@moroto.mountain
Tested-by: Amadeusz Sławiński <amadeuszx.slawinski@xxxxxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20230706155357.3470-1-tiwai@xxxxxxx
Signed-off-by: Takashi Iwai <tiwai@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
sound/core/jack.c | 15 +++++++--------
1 file changed, 7 insertions(+), 8 deletions(-)
--- a/sound/core/jack.c
+++ b/sound/core/jack.c
@@ -654,6 +654,7 @@ void snd_jack_report(struct snd_jack *ja
struct snd_jack_kctl *jack_kctl;
unsigned int mask_bits = 0;
#ifdef CONFIG_SND_JACK_INPUT_DEV
+ struct input_dev *idev;
int i;
#endif
@@ -670,17 +671,15 @@ void snd_jack_report(struct snd_jack *ja
status & jack_kctl->mask_bits);
#ifdef CONFIG_SND_JACK_INPUT_DEV
- mutex_lock(&jack->input_dev_lock);
- if (!jack->input_dev) {
- mutex_unlock(&jack->input_dev_lock);
+ idev = input_get_device(jack->input_dev);
+ if (!idev)
return;
- }
for (i = 0; i < ARRAY_SIZE(jack->key); i++) {
int testbit = ((SND_JACK_BTN_0 >> i) & ~mask_bits);
if (jack->type & testbit)
- input_report_key(jack->input_dev, jack->key[i],
+ input_report_key(idev, jack->key[i],
status & testbit);
}
@@ -688,13 +687,13 @@ void snd_jack_report(struct snd_jack *ja
int testbit = ((1 << i) & ~mask_bits);
if (jack->type & testbit)
- input_report_switch(jack->input_dev,
+ input_report_switch(idev,
jack_switch_types[i],
status & testbit);
}
- input_sync(jack->input_dev);
- mutex_unlock(&jack->input_dev_lock);
+ input_sync(idev);
+ input_put_device(idev);
#endif /* CONFIG_SND_JACK_INPUT_DEV */
}
EXPORT_SYMBOL(snd_jack_report);
Patches currently in stable-queue which might be from tiwai@xxxxxxx are
queue-6.4/alsa-ac97-fix-possible-null-dereference-in-snd_ac97_.patch
queue-6.4/alsa-hda-realtek-enable-mute-micmute-leds-and-limit-mic-boost-on-elitebook.patch
queue-6.4/alsa-pcm-fix-potential-data-race-at-pcm-memory-allocation-helpers.patch
queue-6.4/alsa-jack-fix-mutex-call-in-snd_jack_report.patch
queue-6.4/alsa-hda-realtek-add-quirk-for-clevo-npx0snx.patch
