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

[Dmitry Vyukov]

On Tue, Mar 9, 2021 at 12:38 PM Takashi Iwai <tiwai at suse.de> wrote:
>
> 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")


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