Hello Amadeusz Sławiński,
The patch 1b6a6fc5280e: "ALSA: jack: Access input_dev under mutex"
from Apr 12, 2022, leads to the following Smatch static checker
warning:
sound/core/jack.c:673 snd_jack_report()
warn: sleeping in atomic context
sound/core/jack.c
663 jack->hw_status_cache = status;
664
665 list_for_each_entry(jack_kctl, &jack->kctl_list, list)
666 if (jack_kctl->sw_inject_enable)
667 mask_bits |= jack_kctl->mask_bits;
668 else
669 snd_kctl_jack_report(jack->card, jack_kctl->kctl,
670 status & jack_kctl->mask_bits);
671
672 #ifdef CONFIG_SND_JACK_INPUT_DEV
--> 673 mutex_lock(&jack->input_dev_lock);
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
That patch adds this mutex but we can't take mutex because we're already
holding a spinlock. The problematic call trees are:
virtsnd_event_notify_cb() <- disables preempt
virtsnd_disable_event_vq() <- disables preempt
-> virtsnd_event_dispatch()
-> virtsnd_jack_event()
-> snd_jack_report()
The virtsnd_event_notify_cb() and virtsnd_disable_event_vq() functions
take the spin_lock_irqsave(&queue->lock, flags);
regards,
dan carpenter
