Re: KMSAN: uninit-value in get_term_name

From: Takashi Iwai
Date: Mon Oct 28 2019 - 09:13:26 EST

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").