linux-kernel - [ 10/82] ALSA: usb-audio: Fix races at disconnection in mixer

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Message-Id: <20121114053935.240622234@decadent.org.uk>
Date:	Wed, 14 Nov 2012 05:39:43 +0000
From:	Ben Hutchings <ben@...adent.org.uk>
To:	linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:	akpm@...ux-foundation.org, alan@...rguk.ukuu.org.uk,
	Takashi Iwai <tiwai@...e.de>,
	Matthieu CASTET <matthieu.castet@...rot.com>
Subject: [ 10/82] ALSA: usb-audio: Fix races at disconnection in mixer_quirks.c

3.2-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Takashi Iwai <tiwai@...e.de>

commit 888ea7d5ac6815ba16b3b3a20f665a92c7af6724 upstream.

Similar like the previous commit, cover with chip->shutdown_rwsem
and chip->shutdown checks.

Reported-by: Matthieu CASTET <matthieu.castet@...rot.com>
Signed-off-by: Takashi Iwai <tiwai@...e.de>
Signed-off-by: Ben Hutchings <ben@...adent.org.uk>
---
 sound/usb/mixer_quirks.c | 37 +++++++++++++++++++++++++++++++++----
 1 file changed, 33 insertions(+), 4 deletions(-)

diff --git a/sound/usb/mixer_quirks.c b/sound/usb/mixer_quirks.c
index ab125ee..38a607a 100644
--- a/sound/usb/mixer_quirks.c
+++ b/sound/usb/mixer_quirks.c
@@ -186,6 +186,11 @@ static int snd_audigy2nx_led_put(struct snd_kcontrol *kcontrol, struct snd_ctl_e
 	if (value > 1)
 		return -EINVAL;
 	changed = value != mixer->audigy2nx_leds[index];
+	down_read(&mixer->chip->shutdown_rwsem);
+	if (mixer->chip->shutdown) {
+		err = -ENODEV;
+		goto out;
+	}
 	if (mixer->chip->usb_id == USB_ID(0x041e, 0x3042))
 		err = snd_usb_ctl_msg(mixer->chip->dev,
 			      usb_sndctrlpipe(mixer->chip->dev, 0), 0x24,
@@ -202,6 +207,8 @@ static int snd_audigy2nx_led_put(struct snd_kcontrol *kcontrol, struct snd_ctl_e
 			      usb_sndctrlpipe(mixer->chip->dev, 0), 0x24,
 			      USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_OTHER,
 			      value, index + 2, NULL, 0);
+ out:
+	up_read(&mixer->chip->shutdown_rwsem);
 	if (err < 0)
 		return err;
 	mixer->audigy2nx_leds[index] = value;
@@ -295,11 +302,16 @@ static void snd_audigy2nx_proc_read(struct snd_info_entry *entry,
 
 	for (i = 0; jacks[i].name; ++i) {
 		snd_iprintf(buffer, "%s: ", jacks[i].name);
-		err = snd_usb_ctl_msg(mixer->chip->dev,
+		down_read(&mixer->chip->shutdown_rwsem);
+		if (mixer->chip->shutdown)
+			err = 0;
+		else
+			err = snd_usb_ctl_msg(mixer->chip->dev,
 				      usb_rcvctrlpipe(mixer->chip->dev, 0),
 				      UAC_GET_MEM, USB_DIR_IN | USB_TYPE_CLASS |
 				      USB_RECIP_INTERFACE, 0,
 				      jacks[i].unitid << 8, buf, 3);
+		up_read(&mixer->chip->shutdown_rwsem);
 		if (err == 3 && (buf[0] == 3 || buf[0] == 6))
 			snd_iprintf(buffer, "%02x %02x\n", buf[1], buf[2]);
 		else
@@ -329,10 +341,15 @@ static int snd_xonar_u1_switch_put(struct snd_kcontrol *kcontrol,
 	else
 		new_status = old_status & ~0x02;
 	changed = new_status != old_status;
-	err = snd_usb_ctl_msg(mixer->chip->dev,
+	down_read(&mixer->chip->shutdown_rwsem);
+	if (mixer->chip->shutdown)
+		err = -ENODEV;
+	else
+		err = snd_usb_ctl_msg(mixer->chip->dev,
 			      usb_sndctrlpipe(mixer->chip->dev, 0), 0x08,
 			      USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_OTHER,
 			      50, 0, &new_status, 1);
+	up_read(&mixer->chip->shutdown_rwsem);
 	if (err < 0)
 		return err;
 	mixer->xonar_u1_status = new_status;
@@ -371,11 +388,17 @@ static int snd_nativeinstruments_control_get(struct snd_kcontrol *kcontrol,
 	u8 bRequest = (kcontrol->private_value >> 16) & 0xff;
 	u16 wIndex = kcontrol->private_value & 0xffff;
 	u8 tmp;
+	int ret;
 
-	int ret = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0), bRequest,
+	down_read(&mixer->chip->shutdown_rwsem);
+	if (mixer->chip->shutdown)
+		ret = -ENODEV;
+	else
+		ret = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0), bRequest,
 				  USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN,
 				  0, cpu_to_le16(wIndex),
 				  &tmp, sizeof(tmp), 1000);
+	up_read(&mixer->chip->shutdown_rwsem);
 
 	if (ret < 0) {
 		snd_printk(KERN_ERR
@@ -396,11 +419,17 @@ static int snd_nativeinstruments_control_put(struct snd_kcontrol *kcontrol,
 	u8 bRequest = (kcontrol->private_value >> 16) & 0xff;
 	u16 wIndex = kcontrol->private_value & 0xffff;
 	u16 wValue = ucontrol->value.integer.value[0];
+	int ret;
 
-	int ret = usb_control_msg(dev, usb_sndctrlpipe(dev, 0), bRequest,
+	down_read(&mixer->chip->shutdown_rwsem);
+	if (mixer->chip->shutdown)
+		ret = -ENODEV;
+	else
+		ret = usb_control_msg(dev, usb_sndctrlpipe(dev, 0), bRequest,
 				  USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_OUT,
 				  cpu_to_le16(wValue), cpu_to_le16(wIndex),
 				  NULL, 0, 1000);
+	up_read(&mixer->chip->shutdown_rwsem);
 
 	if (ret < 0) {
 		snd_printk(KERN_ERR


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