Re: [PATCH] Advertise PPPoE MTU / avoid memory leak.

From: Michal Ostrowski
Date: Mon Sep 25 2006 - 14:18:19 EST

On Sun, 2006-09-24 at 18:41 -0700, David Miller wrote:
> From: Michal Ostrowski <mostrows@xxxxxxxxxxxxx>
> Date: Sun, 24 Sep 2006 07:29:25 -0500
> > 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.
> There is a well defined policy about who frees the SKB or has
> ownership of it based upon dev->hard_start_xmit() return values.
> Any driver deviating from this set of rules should simply be
> audited and fixed, as needed.
> But, no matter, your change is buggy and we can't apply your
> patch (even if it does fix a leak in some legitimate case)
> because it introduces an obvious double-free bug.

Yup. I'll resubmit a fixed one.

Michal Ostrowski <mostrows@xxxxxxxxxxxxx>

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