On 18/02/16 16:47, Charles Keepax wrote:
> Lockdep warns of a potential lock inversion, i2s->lock is held numerous
> times whilst we are under the substream lock (snd_pcm_stream_lock). If
> we use the IRQ unsafe spin lock calls, you can also end up locking
> snd_pcm_stream_lock whilst under i2s->lock (if an IRQ happens whilst we
> are holding i2s->lock). This could result in deadlock.
>
> [ 18.147001] CPU0 CPU1
> [ 18.151509] ---- ----
> [ 18.156022] lock(&(&pri_dai->spinlock)->rlock);
> [ 18.160701] local_irq_disable();
> [ 18.166622] lock(&(&substream->self_group.lock)->rlock);
> [ 18.174595] lock(&(&pri_dai->spinlock)->rlock);
> [ 18.181806] <Interrupt>
> [ 18.184408] lock(&(&substream->self_group.lock)->rlock);
> [ 18.190045]
> [ 18.190045] *** DEADLOCK ***
>
> This patch changes to using the irq safe spinlock calls, to avoid this
> issue.
>
> Fixes: ce8bcdbb61d9 ("ASoC: samsung: i2s: Protect more registers with a spinlock")
> Signed-off-by: Charles Keepax <ckeepax@xxxxxxxxxxxxxxxxxxxxxxxxxxx>
Acked-by: Sylwester Nawrocki <s.nawrocki@xxxxxxxxxxx>
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