[PATCH 4.4 111/113] ALSA: line6: Fix POD sysfs attributes segfault

Greg Kroah-Hartman
2016-09-05T16:58:18Z

From: Andrej Krutak <dev@andree.sk>

commit b027d11263836a0cd335520175257dcb99b43757 upstream.

The commit 02fc76f6a changed base of the sysfs attributes from device to card.
The "show" callbacks dereferenced wrong objects because of this.

Fixes: 02fc76f6a7db ('ALSA: line6: Create sysfs via snd_card_add_dev_attr()')
Reviewed-by: Stefan Hajnoczi <stefanha@gmail.com>
Signed-off-by: Andrej Krutak <dev@andree.sk>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
sound/usb/line6/pod.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)

--- a/sound/usb/line6/pod.c
+++ b/sound/usb/line6/pod.c
@@ -244,8 +244,8 @@ static int pod_set_system_param_int(stru
static ssize_t serial_number_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
- struct usb_interface *interface = to_usb_interface(dev);
- struct usb_line6_pod *pod = usb_get_intfdata(interface);
+ struct snd_card *card = dev_to_snd_card(dev);
+ struct usb_line6_pod *pod = card->private_data;

return sprintf(buf, "%u\n", pod->serial_number);
}
@@ -256,8 +256,8 @@ static ssize_t serial_number_show(struct
static ssize_t firmware_version_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
- struct usb_interface *interface = to_usb_interface(dev);
- struct usb_line6_pod *pod = usb_get_intfdata(interface);
+ struct snd_card *card = dev_to_snd_card(dev);
+ struct usb_line6_pod *pod = card->private_data;

return sprintf(buf, "%d.%02d\n", pod->firmware_version / 100,
pod->firmware_version % 100);
@@ -269,8 +269,8 @@ static ssize_t firmware_version_show(str
static ssize_t device_id_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
- struct usb_interface *interface = to_usb_interface(dev);
- struct usb_line6_pod *pod = usb_get_intfdata(interface);
+ struct snd_card *card = dev_to_snd_card(dev);
+ struct usb_line6_pod *pod = card->private_data;

return sprintf(buf, "%d\n", pod->device_id);
}