On Sat, 2006-09-23 at 14:56 -0700, David Miller wrote:
> From: [email protected]
> Date: Sat, 23 Sep 2006 12:30:23 -0500
>
> > __pppoe_xmit must free any skb it allocates if there is an error
> > submitting the skb downstream.
>
> This isn't right, dev_queue_xmit() can return -ENETDOWN and still
> free the SKB, so your change will cause the SKB to be freed up
> twice in that case, from dev_queue_xmit():
>
> rc = -ENETDOWN;
> rcu_read_unlock_bh();
>
> out_kfree_skb:
> kfree_skb(skb);
> return rc;
>
> dev_queue_xmit() is basically expected to consume the packet,
> error or not.
>
> What case of calling dev_queue_xmit() did you discover that did not
> kfree the SKB on error? We should fix that. On a quick scan on the
> entire dev_queue_xmit() implmentation, I cannot find such a case.
>
I think the call path via dev->hard_start_xmit, if it fails, may result
in an skb not being freed. This appears to be the case with the e100.c
driver. The qdisc_restart path to dev->hard_start_xmit also appears
susceptible to this. It appears that not all devices agree as to who
should clean-up an skb on error.
--
Michal Ostrowski <[email protected]>
-
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/
[Index of Archives]
[Kernel Newbies]
[Netfilter]
[Bugtraq]
[Photo]
[Stuff]
[Gimp]
[Yosemite News]
[MIPS Linux]
[ARM Linux]
[Linux Security]
[Linux RAID]
[Video 4 Linux]
[Linux for the blind]
[Linux Resources]
