Re: Question on lockdep and MAX_LOCK_DEPTH

From: Steven Rostedt
Date: Wed Feb 06 2013 - 11:07:26 EST


On Wed, 2013-02-06 at 07:56 -0800, Ben Greear wrote:

> > I'm 99% sure that the bug is in your modifications.
>
> I'm sorry, I tried to make that clear.

You said it was an out of tree module, I didn't realize it had changes
to the core Linux as well.


> My tree is here, minus a few debugging patches related to this bug:
>
> http://dmz2.candelatech.com/git/gitweb.cgi?p=linux-3.7.dev.y/.git;a=summary

Here's your bug:

3319 list_for_each_entry_rcu(ptype, &ptype_all, list) {
3320 if (!ptype->dev || ptype->dev == skb->dev) {
3321 if (pt_prev) {
3322 ret = deliver_skb(skb, pt_prev, orig_dev);
3323 if (ret == NET_RX_CONSUMED) {
3324 kfree_skb(skb); /* we made a copy in deliver_skb */
3325 goto out;
3326 }
3327 }

One of many. All those "goto out;"s skip the rcu_read_unlock().

-- Steve


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