On Tue, 27 May 2014 20:25:41 +0200 Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote: > Nope, its really IRQs. > > do_exit() > exit_itimers() > itimer_delete() > spin_lock_irqsave(&timer->it_lock, &flags); > timer_delete_hook(timer); > kc->timer_del(timer) := posix_cpu_timer_del() > put_task_struct() > __put_task_struct() > task_numa_free() > spin_lock(&grp->lock); > > Which nests the grp->lock inside the timer->it_lock, and where the > timer->it_lock is IRQ-safe, the grp->lock is not. > > This allows for IRQ deadlocks. Ah crap. I did a search on all the callers of put_task_struct(), and somehow missed this one. Yep, I was looking for places that called this while holding other irq safe locks. -- Steve -- To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
