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From:   Andrey Konovalov <andreyknvl@google.com>
Date:   Mon, 12 Aug 2019 14:03:57 +0200
Message-ID: <CAAeHK+ztV==ojaqueEzM4O5Bq_qdxVKhg8stvgT-VdMEs8GBtw@mail.gmail.com>
Subject: Re: KASAN: use-after-free Read in usb_kill_urb
To:     Alan Stern <stern@rowland.harvard.edu>
Cc:     syzbot <syzbot+22ae4e3b9fcc8a5c153a@syzkaller.appspotmail.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        "Gustavo A. R. Silva" <gustavo@embeddedor.com>,
        LKML <linux-kernel@vger.kernel.org>,
        USB list <linux-usb@vger.kernel.org>,
        syzkaller-bugs <syzkaller-bugs@googlegroups.com>
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On Fri, Aug 9, 2019 at 10:52 PM Alan Stern <stern@rowland.harvard.edu> wrote:
>
> On Fri, 9 Aug 2019, syzbot wrote:
>
> > Hello,
> >
> > syzbot has tested the proposed patch and the reproducer did not trigger
> > crash:
> >
> > Reported-and-tested-by:
> > syzbot+22ae4e3b9fcc8a5c153a@syzkaller.appspotmail.com
> >
> > Tested on:
> >
> > commit:         e96407b4 usb-fuzzer: main usb gadget fuzzer driver
> > git tree:       https://github.com/google/kasan.git
> > kernel config:  https://syzkaller.appspot.com/x/.config?x=cfa2c18fb6a8068e
> > compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
> > patch:          https://syzkaller.appspot.com/x/patch.diff?x=173f2d2c600000
> >
> > Note: testing is done by a robot and is best-effort only.
>
> This shows that this bug is a duplicate of extid=30cf45ebfe0b0c4847a1.

Let's mark it as one:

#syz dup: KASAN: use-after-free Read in ld_usb_release

I'll also mark all bugs that involve ldusb as duplicates, as they all
likely are.

> This fact is also visible in the console logs; both have lines saying
> something like:
>
> [  549.416341][   T22] sysfs: cannot create duplicate filename '/class/usbmisc/ldusb0'
>
> and
>
> [  549.958755][   T22] ldusb 1-1:0.28: Not able to get a minor for this device.
>
> preceding the invalid access.
>
> Alan Stern
>