linux-kernel - [PATCH v2] staging: sound: Adjust mutex unlock order

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-ID: <20250716081804.727623-1-karanja99erick@gmail.com>
Date: Wed, 16 Jul 2025 11:18:04 +0300
From: Erick Karanja <karanja99erick@...il.com>
To: perex@...ex.cz,
	tiwai@...e.com
Cc: linux-sound@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	julia.lawall@...ia.fr,
	Erick Karanja <karanja99erick@...il.com>
Subject: [PATCH v2] staging: sound: Adjust mutex unlock order

The mutexes qdev_mutex and chip->mutex are acquired in that order
throughout the driver. To preserve proper lock hierarchy and avoid
potential deadlocks, they must be released in the reverse
order of acquisition.

This change reorders the unlock sequence to first release chip->mutex
followed by qdev_mutex, ensuring consistency with the locking pattern.

changes since v1:
   - Applied the unlock reordering in other functions with this pattern.

Signed-off-by: Erick Karanja <karanja99erick@...il.com>
---
 sound/usb/qcom/qc_audio_offload.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/sound/usb/qcom/qc_audio_offload.c b/sound/usb/qcom/qc_audio_offload.c
index 3543b5a53592..a25c5a531690 100644
--- a/sound/usb/qcom/qc_audio_offload.c
+++ b/sound/usb/qcom/qc_audio_offload.c
@@ -825,8 +825,8 @@ static int uaudio_sideband_notifier(struct usb_interface *intf,
 		}
 	}
 
-	mutex_unlock(&qdev_mutex);
 	mutex_unlock(&chip->mutex);
+	mutex_unlock(&qdev_mutex);
 
 	return 0;
 }
@@ -1865,8 +1865,8 @@ static void qc_usb_audio_offload_disconnect(struct snd_usb_audio *chip)
 
 	/* Device has already been cleaned up, or never populated */
 	if (!dev->chip) {
-		mutex_unlock(&qdev_mutex);
 		mutex_unlock(&chip->mutex);
+		mutex_unlock(&qdev_mutex);
 		return;
 	}
 
@@ -1921,8 +1921,8 @@ static void qc_usb_audio_offload_suspend(struct usb_interface *intf,
 
 	uaudio_send_disconnect_ind(chip);
 
-	mutex_unlock(&qdev_mutex);
 	mutex_unlock(&chip->mutex);
+	mutex_unlock(&qdev_mutex);
 }
 
 static struct snd_usb_platform_ops offload_ops = {
-- 
2.43.0