ALSA: usb-audio: fix use after free in usb_audio_disconnect

commit c5aa956eaeb05fe87e33433d7fd9f5e4d23c7416 upstream.

The problem was in wrong "if" placement. chip->quirk_type is freed
in snd_card_free_when_closed(), but inside if statement it's accesed.

Fixes: 9799110825db ("ALSA: usb-audio: Disable USB autosuspend properly in setup_disable_autosuspend()")
Signed-off-by: Pavel Skripkin <paskripkin@gmail.com>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/16da19126ff461e5e64a9aec648cce28fb8ed73e.1615242183.git.paskripkin@gmail.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/sound/usb/card.c b/sound/usb/card.c
index 478bcbf..fc7c359 100644 (file)
--- a/sound/usb/card.c
+++ b/sound/usb/card.c
@@ -907,6 +907,9 @@ static void usb_audio_disconnect(struct usb_interface *intf)
                }
        }
 
+       if (chip->quirk_type & QUIRK_SETUP_DISABLE_AUTOSUSPEND)
+               usb_enable_autosuspend(interface_to_usbdev(intf));
+
        chip->num_interfaces--;
        if (chip->num_interfaces <= 0) {
                usb_chip[chip->index] = NULL;
@@ -915,9 +918,6 @@ static void usb_audio_disconnect(struct usb_interface *intf)
        } else {
                mutex_unlock(&register_mutex);
        }
-
-       if (chip->quirk_type & QUIRK_SETUP_DISABLE_AUTOSUSPEND)
-               usb_enable_autosuspend(interface_to_usbdev(intf));
 }
 
 /* lock the shutdown (disconnect) task and autoresume */