Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::3:5 as permitted sender) client-ip=2620:137:e000::3:5;
MIME-Version: 1.0
References: <CABOYnLyCRyK4qpS2X8ssA6yxCDtEWR3dSsee2Lm6VCQUyD07VQ@mail.gmail.com>
 <2023112332-award-fanciness-2bcf@gregkh>
In-Reply-To: <2023112332-award-fanciness-2bcf@gregkh>
From:   Aleksandr Nogikh <nogikh@google.com>
Date:   Thu, 23 Nov 2023 10:32:26 +0100
Message-ID: <CANp29Y6ge-AhM+Byt3imGOpctRsgWiqBN-reuKvOJAzxBsTYLw@mail.gmail.com>
Subject: Re: [syzbot] [kernel?] general protection fault in joydev_connect
To:     "gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>
Cc:     xingwei lee <xrivendell7@gmail.com>,
        "syzbot+786b124fe4ce4dc99357@syzkaller.appspotmail.com" 
        <syzbot+786b124fe4ce4dc99357@syzkaller.appspotmail.com>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "rafael@kernel.org" <rafael@kernel.org>,
        "syzkaller-bugs@googlegroups.com" <syzkaller-bugs@googlegroups.com>,
        Dmitry Vyukov <dvyukov@google.com>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
Precedence: bulk

On Thu, Nov 23, 2023 at 9:55=E2=80=AFAM gregkh@linuxfoundation.org
<gregkh@linuxfoundation.org> wrote:
>
> On Wed, Nov 22, 2023 at 07:55:50PM +0800, xingwei lee wrote:
> > Hi. I have reproduced this bug with repro.txt and repro.c below:
> >
> > repro.txt
> > r0 =3D openat$uinput(0xffffffffffffff9c, &(0x7f0000000500), 0x802, 0x0)
> > ioctl$UI_DEV_SETUP(r0, 0x405c5503, &(0x7f0000000080)=3D{{0x0, 0xffff,
> > 0x3}, 'syz0\x00'})
> > ioctl$UI_DEV_CREATE(r0, 0x5501) (fail_nth: 51)
>
> You are using fault injection, which, by it's very name, causes faults :)

But those injected failures (that do not break the kernel, but just
emulate an error returned from a function that should be expected to
sometimes return an error) still should not lead to general protection
fault panics, shouldn't they?

--=20
Aleksandr

>
> Can you reproduce it without causing faults in the kernel?  And if so,
> can you create a patch to fix this?
>
> thanks,
>
> greg k-h
>