[syzbot] KASAN: use-after-free Read in usb_audio_disconnect

[Takashi Iwai]

On Tue, 09 Mar 2021 12:32:18 +0100,
syzbot wrote:
> 
> Hello,
> 
> syzbot found the following issue on:
> 
> HEAD commit:    4641b323 Add linux-next specific files for 20210305
> git tree:       linux-next
> console output: https://syzkaller.appspot.com/x/log.txt?x=103252ead00000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=b87b6a083d302a90
> dashboard link: https://syzkaller.appspot.com/bug?extid=ffad4c74b3b3ea3aa9c3
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=1122d35cd00000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=17f6476cd00000
> 
> The issue was bisected to:
> 
> commit 9799110825dba087c2bdce886977cf84dada2005
> Author: Kai-Heng Feng <kai.heng.feng at canonical.com>
> Date:   Thu Mar 4 04:34:16 2021 +0000
> 
>     ALSA: usb-audio: Disable USB autosuspend properly in setup_disable_autosuspend()
> 
> bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=166d91ead00000
> final oops:     https://syzkaller.appspot.com/x/report.txt?x=156d91ead00000
> console output: https://syzkaller.appspot.com/x/log.txt?x=116d91ead00000
> 
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+ffad4c74b3b3ea3aa9c3 at syzkaller.appspotmail.com
> Fixes: 9799110825db ("ALSA: usb-audio: Disable USB autosuspend properly in setup_disable_autosuspend()")
> 
> usb 1-1: USB disconnect, device number 2
> ==================================================================
> BUG: KASAN: use-after-free in usb_audio_disconnect+0x750/0x800 sound/usb/card.c:918

This must be fixed by the commit that was already merged to sound.git
tree today:
c5aa956eaeb0 ("ALSA: usb-audio: fix use after free in usb_audio_disconnect")


thanks,

Takashi