[PATCH 5.11 175/306] ALSA: usb-audio: fix use after free in usb_audio_disconnect

Mon, 15 Mar 2021 07:40:52 -0700 

From: Greg Kroah-Hartman <[email protected]>

From: Pavel Skripkin <[email protected]>

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 <[email protected]>
Cc: <[email protected]>
Link: 
https://lore.kernel.org/r/16da19126ff461e5e64a9aec648cce28fb8ed73e.1615242183.git.paskrip...@gmail.com
Signed-off-by: Takashi Iwai <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
 sound/usb/card.c |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

--- a/sound/usb/card.c
+++ b/sound/usb/card.c
@@ -908,6 +908,9 @@ static void usb_audio_disconnect(struct
                }
        }
 
+       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;
@@ -916,9 +919,6 @@ static void usb_audio_disconnect(struct
        } 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 */

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