Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Date:   Mon, 28 Oct 2019 14:55:52 +0100
Message-ID: <s5himo9as9j.wl-tiwai@suse.de>
From:   Takashi Iwai <tiwai@suse.de>
To:     Greg KH <gregkh@linuxfoundation.org>
Cc:     syzbot <syzbot+8f2612936028bfd28f28@syzkaller.appspotmail.com>,
        allison@lohutok.net, alsa-devel@alsa-project.org,
        benquike@gmail.com, dan.carpenter@oracle.com, glider@google.com,
        linux-kernel@vger.kernel.org, perex@perex.cz,
        syzkaller-bugs@googlegroups.com, tglx@linutronix.de,
        tiwai@suse.com, wang6495@umn.edu, yuehaibing@huawei.com
Subject: Re: KMSAN: uninit-value in get_term_name
In-Reply-To: <20191028133050.GA13691@kroah.com>
References: <000000000000f838060595f602a7@google.com>
        <s5hr22xau8f.wl-tiwai@suse.de>
        <20191028133050.GA13691@kroah.com>
User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI/1.14.6 (Maruoka)
 FLIM/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL/10.8 Emacs/25.3
 (x86_64-suse-linux-gnu) MULE/6.0 (HANACHIRUSATO)
MIME-Version: 1.0 (generated by SEMI 1.14.6 - "Maruoka")
Content-Type: text/plain; charset=US-ASCII
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Mon, 28 Oct 2019 14:30:50 +0100,
Greg KH wrote:
> 
> On Mon, Oct 28, 2019 at 02:13:20PM +0100, Takashi Iwai wrote:
> > On Mon, 28 Oct 2019 11:32:07 +0100,
> > syzbot wrote:
> > > 
> > > Uninit was stored to memory at:
> > >  kmsan_save_stack_with_flags mm/kmsan/kmsan.c:151 [inline]
> > >  kmsan_internal_chain_origin+0xbd/0x180 mm/kmsan/kmsan.c:319
> > >  __msan_chain_origin+0x6b/0xd0 mm/kmsan/kmsan_instr.c:179
> > >  parse_term_proc_unit+0x73d/0x7e0 sound/usb/mixer.c:896
> > >  __check_input_term+0x13ef/0x2360 sound/usb/mixer.c:989
> > 
> > So this comes from the invalid descriptor for a processing unit, and
> > it's very likely the same issue as already spotted -- the validator up
> > to 5.3-rc4 had a bug that passed the invalid descriptor falsely.
> > This should have been covered by 5.3-rc5, commit ba8bf0967a15 ("ALSA:
> > usb-audio: Fix copy&paste error in the validator").
> 
> SHould we be backporting the validator to any older kernels as well?

Yes, that would be nice.  I didn't mark them for stable just because
they are a bit largish and wanted to let them tested for 5.4 for a
while.

The following commits are relevant (from top/old to bottom/new).

57f8770620e9b51c61089751f0b5ad3dbe376ff2
    ALSA: usb-audio: More validations of descriptor units
68e9fde245591d18200f8a9054cac22339437adb
    ALSA: usb-audio: Simplify parse_audio_unit()
52c3e317a857091fd746e15179a637f32be4d337
    ALSA: usb-audio: Unify the release of usb_mixer_elem_info objects
b8e4f1fdfa422398c2d6c47bfb7d1feb3046d70a
    ALSA: usb-audio: Remove superfluous bLength checks
e0ccdef92653f8867e2d1667facfd3c23699f540
    ALSA: usb-audio: Clean up check_input_term()
60849562a5db4a1eee2160167e4dce4590d3eafe
    ALSA: usb-audio: Fix possible NULL dereference at create_yamaha_midi_quirk()
b39e077fcb283dd96dd251a3abeba585402c61fe
    ALSA: usb-audio: remove some dead code
ba8bf0967a154796be15c4983603aad0b05c3138
    ALSA: usb-audio: Fix copy&paste error in the validator


thanks,

Takashi