[syzbot] WARNING in snd_usbmidi_output_open

[Takashi Iwai]

On Sat, 12 Nov 2022 14:35:06 +0100,
Mark Brown wrote:
> 
> On Sat, Nov 12, 2022 at 05:29:21AM -0800, syzbot wrote:
> > syzbot has bisected this issue to:
> > 
> > commit 4f8ed19593872b710f27bbc3b7a9ce03310efc57
> > Author: Mark Brown <broonie at kernel.org>
> > Date:   Thu Jun 2 13:10:58 2022 +0000
> > 
> >     ASoC: tfa9879: Use modern ASoC DAI format terminology
> 
> This bisection really doesn't seem credible for an issue in a different
> driver...  The tfa9879 is neither a USB nor MIDI device, and the commit
> in question is a stylistic update.

Yes, the bisection result is bogus.

And, the problem here is just a kernel WARNING produced by
snd_BUG_ON() macro usage, and the check itself is valid.
We just need to drop snd_BUG_ON() wrapping.

Will submit the fix later.


thanks,

Takashi