Patch "ALSA: usb-audio: fix use after free in usb_audio_disconnect" has been added to the 5.11-stable tree

[<gregkh@xxxxxxxxxxxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

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

to the 5.11-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     alsa-usb-audio-fix-use-after-free-in-usb_audio_disconnect.patch
and it can be found in the queue-5.11 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.


>From c5aa956eaeb05fe87e33433d7fd9f5e4d23c7416 Mon Sep 17 00:00:00 2001
From: Pavel Skripkin <paskripkin@xxxxxxxxx>
Date: Tue, 9 Mar 2021 01:30:57 +0300
Subject: ALSA: usb-audio: fix use after free in usb_audio_disconnect

From: Pavel Skripkin <paskripkin@xxxxxxxxx>

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@xxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/16da19126ff461e5e64a9aec648cce28fb8ed73e.1615242183.git.paskripkin@xxxxxxxxx
Signed-off-by: Takashi Iwai <tiwai@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 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 */


Patches currently in stable-queue which might be from paskripkin@xxxxxxxxx are

queue-5.11/alsa-usb-audio-fix-use-after-free-in-usb_audio_disconnect.patch
queue-5.11/alsa-usb-audio-fix-null-ptr-dereference-in-usb_audio_probe.patch