Re: ACPI/HT or Packet Scheduler BUG?

[Tarhon-Onu Victor]

On Tue, 12 Apr 2005, Tarhon-Onu Victor wrote:

> 	So the problem should be looked in that changes to the pkt sched API, 
> the patch containing only those changes is at

	The bug is in this portion of code from net/sched/sch_generic.c, 
in the qdisc_destroy() function:

==
     list_for_each_entry(cq, &cql, list)
          list_for_each_entry_safe(q, n, &qdisc->dev->qdisc_list, list)
               if (TC_H_MAJ(q->parent) == TC_H_MAJ(cq->handle)) {
                    if (q->ops->cl_ops == NULL)
                         list_del_init(&q->list);
                    else
                         list_move_tail(&q->list, &cql);
               }
     list_for_each_entry_safe(cq, n, &cql, list)
          list_del_init(&cq->list);
==

	...and it happens when q->ops->cl_ops is NULL and 
list_del_init(&q->list) is executed.

	The stuff from include/linux/list.h looks ok, it seems like one 
of those two iterations (list_for_each_entry() and 
list_for_each_entry_safe()) enters an endless loop when an element is 
removed from the list under some circumstances.

--
Tarhon-Onu Victor
Area Technical Coordinator
RDS Iasi - Network Operations Center
www.rdsnet.ro, www.rdstel.ro, www.rdslink.ro
Phone: +40-232-218385; Fax: +40-232-260099
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