Re: next-0519 on thinkpad x60: sound related? window manager crash

Takashi Iwai
2020-06-11T17:12:13Z

On Thu, 11 Jun 2020 16:51:55 +0200,
Alex Xu (Hello71) wrote:
>
> Excerpts from Takashi Iwai's message of June 9, 2020 11:12 am:
> > On Tue, 09 Jun 2020 13:47:33 +0200,
> > Christoph Hellwig wrote:
> >>
> >> Alex, can you try this patch?
> >
> > Also could you check whether just papering over the memset() call
> > alone avoids the crash like below? For PulseAudio and dmix/dsnoop,
> > it's the only code path that accesses the vmapped buffer, I believe.
> >
> > If this works more or less, I'll cook a more comprehensive fix.
> >
> >
> > thanks,
> >
> > Takashi
> >
> > --- a/sound/core/pcm_native.c
> > +++ b/sound/core/pcm_native.c
> > @@ -754,9 +754,11 @@ static int snd_pcm_hw_params(struct snd_pcm_substream *substream,
> > while (runtime->boundary * 2 <= LONG_MAX - runtime->buffer_size)
> > runtime->boundary *= 2;
> >
> > +#if 0
> > /* clear the buffer for avoiding possible kernel info leaks */
> > if (runtime->dma_area && !substream->ops->copy_user)
> > memset(runtime->dma_area, 0, runtime->dma_bytes);
> > +#endif
> >
> > snd_pcm_timer_resolution_change(substream);
> > snd_pcm_set_state(substream, SNDRV_PCM_STATE_SETUP);
> >
>
> Sorry, this patch doesn't work for me with SME off using abfbb29297c2.
> David's newest submitted patch works for me, which I already replied to
> separately.

Thanks, so something still missing in the mmap handling, I guess.

I've worked on two different branches for potential fixes of your
problems. Could you test topic/dma-fix and topic/dma-fix2 branches?
git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound.git
Just pull one of them onto Linus' git HEAD.

I guess we'll go with David's new patch, but still it's interesting
whether my changes do anything good actually.

Takashi