Patrick McHardy wrote: > Chuck Ebbert wrote: > >>Limit of 1 is forbidden, crashes with 2, works with 3: >> >>>From disassembling sch_sfq.ko it seems that it is on line 360 of sch_sfq.c: >> sch->qstats.backlog -= skb->len; >>where "skb" is an invalid pointer: > > > > Is it a NULL pointer or something random?
Never mind, I found the reason. When enqueuing the packet, sfq_enqueue contains an off-by-one in the limit check (which IIRC is there for a reason, but I can't remember right now) and drops the packet again. dev_queue_xmit() calls qdisc_run() anyway and the empty qdisc is dequeued, which is not handled by SFQ. I see three possibilities to fix this (in my preferred order): 1) figure out why the off-by-one is there, if not needed remove 2) don't dequeue qdiscs even once if empty 3) check for NULL in sfq_dequeue So I'll try to remeber why the off-by-one is there .. - To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
