On Sun, 25 Jun 2023 18:22:56 +0200, YE Chengfeng wrote: > > The timer loopback_jiffies_timer_function is executed under > bottom-half softirq context and require a spinlock, thus > other process context code requiring the same lock (i.e., > loopback_trigger, loopback_pointer) can deadlock with the > timer if it is preempted while holding the lock. > > Deadlock scenario: > loopback_trigger > -> spin_lock(&cable->lock); > <timer interrupt> > -> loopback_jiffies_timer_function > -> spin_lock_irqsave(&dpcm->cable->lock, flags); > > Fix the potential deadlock by using spin_lock_irqsave. Similarly like the patch for snd-dummy, this change looks superfluous, too. thanks, Takashi
