• Charles Keepax's avatar
    ASoC: samsung: Use IRQ safe spin lock calls · 48034ae6
    Charles Keepax authored
    commit 316fa9e0 upstream.
    
    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: ce8bcdbb ("ASoC: samsung: i2s: Protect more registers with a spinlock")
    Signed-off-by: default avatarCharles Keepax <ckeepax@opensource.wolfsonmicro.com>
    Tested-by: default avatarAnand Moon <linux.amoon@gmail.com>
    Signed-off-by: default avatarMark Brown <broonie@kernel.org>
    Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
    48034ae6
i2s.c 35.9 KB