On Sun, 25 Jun 2023 17:35:48 +0200, YE Chengfeng wrote: > > The timer dummy_systimer_callback is executed under softirq > context, thus other process context code requiring the same lock > should disable interrupt. Otherwise there would be potential > deadlock issues when the code executing under process context > (i.e., dummy_systimer_pointer, dummy_systimer_start, > dummy_systimer_stop) is preempted by the timer while holding > the lock. > > Deadlock scenario: > dummy_systimer_pointer > -> spin_lock(&dpcm->lock); > <timer interrupt> > -> dummy_systimer_callback > -> spin_lock_irqsave(&dpcm->lock, flags); > > Fix the potential deadlock by using spin_lock_irqsave. Did you really trigger this deadlock, or is just your hypothesis? I'm asking it because basically the deadlock above shouldn't happen; those are called only via PCM trigger and pointer callbacks, and they are always called inside the PCM stream lock, and already irq-disabled. thanks, Takashi
