FAILED: patch "[PATCH] ALSA: core: Check shutdown flag at D0 power-state, too" failed to apply to 5.15-stable tree

FAILED: patch "[PATCH] ALSA: core: Check shutdown flag at D0 power-state, too" failed to apply to 5.15-stable tree

[Sasha Levin]

The patch below does not apply to the 5.15-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y
git checkout FETCH_HEAD
git cherry-pick -x ad63c5b62843895e8c3cd7291ed07cc659df0355
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '20261107060043-failed-5.15-ad63c5b62843@kernel.org' --subject-prefix 'PATCH 5.15.y' 'HEAD^..'

Thanks,
Sasha

------------------ original commit in Linus's tree ------------------

From ad63c5b62843895e8c3cd7291ed07cc659df0355 Mon Sep 17 00:00:00 2001
From: Takashi Iwai <tiwai@suse.de>
Date: Tue, 29 Sep 2026 14:53:41 +0200
Subject: [PATCH] ALSA: core: Check shutdown flag at D0 power-state, too

The snd_power_ref_and_wait() skips the card->shutdown check when the
card is already in D0 state and immediately returns as successful, by
assuming the all-green in D0.  This assumption makes the code after
this sync point behaving as if all power is up and ready, even though
actually it might have been already at the disconnected state.

Add the missing check of shutdown flag there for the more consistent
behavior.

Cc: stable@vger.kernel.org
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Link: https://patch.msgid.link/20260929125346.1478631-2-tiwai@suse.de
---
 sound/core/init.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/sound/core/init.c b/sound/core/init.c
index 1bcb6a2e75507..a51b71812fd9b 100644
--- a/sound/core/init.c
+++ b/sound/core/init.c
@@ -1174,12 +1174,12 @@ EXPORT_SYMBOL(snd_card_file_remove);
 int snd_power_ref_and_wait(struct snd_card *card)
 {
 	snd_power_ref(card);
-	if (snd_power_get_state(card) == SNDRV_CTL_POWER_D0)
-		return 0;
-	wait_event_cmd(card->power_sleep,
-		       card->shutdown ||
-		       snd_power_get_state(card) == SNDRV_CTL_POWER_D0,
-		       snd_power_unref(card), snd_power_ref(card));
+	if (snd_power_get_state(card) != SNDRV_CTL_POWER_D0) {
+		wait_event_cmd(card->power_sleep,
+			       card->shutdown ||
+			       snd_power_get_state(card) == SNDRV_CTL_POWER_D0,
+			       snd_power_unref(card), snd_power_ref(card));
+	}
 	if (card->shutdown) {
 		snd_power_unref(card);
 		return  -ENODEV;
-- 
2.53.0

[PATCH 5.15.y 1/3] ALSA: core: Simplify snd_power_ref_and_wait() with the standard macro

[Sasha Levin]

From: Takashi Iwai <tiwai@suse.de>

[ Upstream commit 8c0ae778e2874f3742bd619000b791d178c187e2 ]

Use wait_event_cmd() macro and simplify snd_power_ref_wait()
implementation.  This may also cover possible races in the current
open code, too.

Reviewed-by: Jaroslav Kysela <perex@perex.cz>
Link: https://lore.kernel.org/r/20220119091050.30125-1-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Stable-dep-of: ad63c5b62843 ("ALSA: core: Check shutdown flag at D0 power-state, too")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 sound/core/init.c | 25 +++++--------------------
 1 file changed, 5 insertions(+), 20 deletions(-)

diff --git a/sound/core/init.c b/sound/core/init.c
index c0e7d4962bbc9..e9465b31f9fda 100644
--- a/sound/core/init.c
+++ b/sound/core/init.c
@@ -1154,29 +1154,14 @@ EXPORT_SYMBOL(snd_card_file_remove);
  */
 int snd_power_ref_and_wait(struct snd_card *card)
 {
-	wait_queue_entry_t wait;
-	int result = 0;
-
 	snd_power_ref(card);
-	/* fastpath */
 	if (snd_power_get_state(card) == SNDRV_CTL_POWER_D0)
 		return 0;
-	init_waitqueue_entry(&wait, current);
-	add_wait_queue(&card->power_sleep, &wait);
-	while (1) {
-		if (card->shutdown) {
-			result = -ENODEV;
-			break;
-		}
-		if (snd_power_get_state(card) == SNDRV_CTL_POWER_D0)
-			break;
-		snd_power_unref(card);
-		set_current_state(TASK_UNINTERRUPTIBLE);
-		schedule_timeout(30 * HZ);
-		snd_power_ref(card);
-	}
-	remove_wait_queue(&card->power_sleep, &wait);
-	return result;
+	wait_event_cmd(card->power_sleep,
+		       card->shutdown ||
+		       snd_power_get_state(card) == SNDRV_CTL_POWER_D0,
+		       snd_power_unref(card), snd_power_ref(card));
+	return card->shutdown ? -ENODEV : 0;
 }
 EXPORT_SYMBOL_GPL(snd_power_ref_and_wait);
 
-- 
2.53.0

[PATCH 5.15.y 2/3] ALSA: core: Fix unintuitive behavior of snd_power_ref_and_wait()

[Sasha Levin]

From: Takashi Iwai <tiwai@suse.de>

[ Upstream commit b113a891252c3fa4fab11ec8c2894a22ecaf278c ]

snd_power_ref_and_wait() takes the power refcount and doesn't leave it
no matter whether it returns an error or not.  However, the majority
of callers don't expect but just returns without unreferencing in the
caller side upon errors.

For addressing the potential refcount unbalance, rather correct the
behavior of snd_power_ref_wait() to unreference upon returning an
error.

Note that the problem above is likely negligible; the function returns
an error only when the sound card is being shutdown, hence it doesn't
matter about the power refcount any longer at such a state.

Fixes: e94fdbd7b25d ("ALSA: control: Track in-flight control read/write/tlv accesses")
Reported-by: WenTao Liang <vulab@iscas.ac.cn>
Closes: https://lore.kernel.org/20260612022121.14329-1-vulab@iscas.ac.cn
Link: https://patch.msgid.link/20260614090507.772540-1-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Stable-dep-of: ad63c5b62843 ("ALSA: core: Check shutdown flag at D0 power-state, too")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 sound/core/init.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/sound/core/init.c b/sound/core/init.c
index e9465b31f9fda..0cd775e913bb7 100644
--- a/sound/core/init.c
+++ b/sound/core/init.c
@@ -1148,7 +1148,7 @@ EXPORT_SYMBOL(snd_card_file_remove);
  * typically around calling control ops.
  *
  * The caller needs to pull down the refcount via snd_power_unref() later
- * no matter whether the error is returned from this function or not.
+ * when this function returns 0.
  *
  * Return: Zero if successful, or a negative error code.
  */
@@ -1161,7 +1161,11 @@ int snd_power_ref_and_wait(struct snd_card *card)
 		       card->shutdown ||
 		       snd_power_get_state(card) == SNDRV_CTL_POWER_D0,
 		       snd_power_unref(card), snd_power_ref(card));
-	return card->shutdown ? -ENODEV : 0;
+	if (card->shutdown) {
+		snd_power_unref(card);
+		return  -ENODEV;
+	}
+	return 0;
 }
 EXPORT_SYMBOL_GPL(snd_power_ref_and_wait);
 
@@ -1178,7 +1182,8 @@ int snd_power_wait(struct snd_card *card)
 	int ret;
 
 	ret = snd_power_ref_and_wait(card);
-	snd_power_unref(card);
+	if (!ret)
+		snd_power_unref(card);
 	return ret;
 }
 EXPORT_SYMBOL(snd_power_wait);
-- 
2.53.0

[PATCH 5.15.y 3/3] ALSA: core: Check shutdown flag at D0 power-state, too

[Sasha Levin]

From: Takashi Iwai <tiwai@suse.de>

[ Upstream commit ad63c5b62843895e8c3cd7291ed07cc659df0355 ]

The snd_power_ref_and_wait() skips the card->shutdown check when the
card is already in D0 state and immediately returns as successful, by
assuming the all-green in D0.  This assumption makes the code after
this sync point behaving as if all power is up and ready, even though
actually it might have been already at the disconnected state.

Add the missing check of shutdown flag there for the more consistent
behavior.

Cc: stable@vger.kernel.org
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Link: https://patch.msgid.link/20260929125346.1478631-2-tiwai@suse.de
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 sound/core/init.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/sound/core/init.c b/sound/core/init.c
index 0cd775e913bb7..be04e64490ebc 100644
--- a/sound/core/init.c
+++ b/sound/core/init.c
@@ -1155,12 +1155,12 @@ EXPORT_SYMBOL(snd_card_file_remove);
 int snd_power_ref_and_wait(struct snd_card *card)
 {
 	snd_power_ref(card);
-	if (snd_power_get_state(card) == SNDRV_CTL_POWER_D0)
-		return 0;
-	wait_event_cmd(card->power_sleep,
-		       card->shutdown ||
-		       snd_power_get_state(card) == SNDRV_CTL_POWER_D0,
-		       snd_power_unref(card), snd_power_ref(card));
+	if (snd_power_get_state(card) != SNDRV_CTL_POWER_D0) {
+		wait_event_cmd(card->power_sleep,
+			       card->shutdown ||
+			       snd_power_get_state(card) == SNDRV_CTL_POWER_D0,
+			       snd_power_unref(card), snd_power_ref(card));
+	}
 	if (card->shutdown) {
 		snd_power_unref(card);
 		return  -ENODEV;
-- 
2.53.0