Messages in this thread | | | Date | Sat, 16 Dec 2000 19:09:56 -0800 (PST) | From | Linus Torvalds <> | Subject | Re: 2.4.0-test13-pre1 lockup: run_task_queue or tty_io are wrong |
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On Sun, 17 Dec 2000, Petr Vandrovec wrote: > my 2.4.0-test13-pre1 just stopped answering to my keystrokes. > I've found that it is looping in tqueue_bh and flush_to_ldisc > still again and again.
Thanks, I think you found the big problem with test12.
> Is current run_task_queue() behavior intentional, or is it > only bug introduced by changing task queue to list based > implementation?
It's a bug.
Ho humm. I'll have to check what the proper fix is. Right now the rule is that nobody can _ever_ remove himself from a task queue, although there is one bad user that does exactly that, and that means that it should be ok to just cache the "next" pointer in run_task_queue(), and make it look something like
static void run_task_queue(task_queue *list) { if (!list_empty(list)) { unsigned long flags; struct list_head *next;
spin_lock_irqsave(&tqueue_lock, flags); next = list->next; while (next != list) { struct list_head *curr; void *arg; void (*f) (void *); struct tq_struct *p;
curr = next; next = next->next; list_del(curr);
p = list_entry(curr, struct tq_struct, list); arg = p->data; f = p->routine; p->sync = 0; spin_unlock_irqrestore(&tqueue_lock, flags);
if (f) f(arg);
spin_lock_irq(&tqueue_lock); } spin_unlock_irqrestore(&tqueue_lock, flags); } } which basically will never re-start at the head if a tq re-inserts iself (side note: new entires are inserted at the end, but if it was already the last entry then re-inserting it will not re-execute it, should this should avoid your problem).
Does this fix the problem for you?
Linus
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