Hi! I'm a newbie here on the list and also as a "kernel hacker". There's a bug reported in bugzilla (Bug 7927), cite:
> In the function __down > > fastcall void __sched __down(struct semaphore * sem) > { > struct task_struct *tsk = current; > DECLARE_WAITQUEUE(wait, tsk); > unsigned long flags; > > tsk->state = TASK_UNINTERRUPTIBLE; > spin_lock_irqsave(&sem->wait.lock, flags); > add_wait_queue_exclusive_locked(&sem->wait, &wait); > ... > } > > > From this code fragment, it sets the tsk->state to TASK_UNINTERRUPTIBLE > before > gets the spinlock. Assume at that moment, a interrupt ocuur and and after the > interrupt handle ends, an other process is scheduled to run (assume the > kernel > is preemptalbe). In this case, the previous process ( its state has set to > TASK_UNINTERRUPTIBLE) has been picked off the run queue, and it has not yet > add > to the wait queue( sem->wait ), so it may be never waited up forever. > I have marked it as rejected as as I can see at the time this function is called, it is guaranteed that ret_from_intr() will not call schedule() on return from an interrupt handler to either kernel space or user space because of the call to macro might_sleep() in semaphore's down(). Am I wrong? Thanks and best regards, Aleksandar Dezelin - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/