netdev - Re: [PATCH bpf-next v10 5/7] bpf: add handling of BPF_LWT_REROUTE to lwt

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Message-ID: <CAPNVh5fkQv1Ov6fmgrakmT-X3qU-FYPsCTii7ONWW3AVe9ppbA@mail.gmail.com>
Date:   Wed, 13 Feb 2019 12:41:13 -0800
From:   Peter Oskolkov <posk@...gle.com>
To:     David Ahern <dsahern@...il.com>
Cc:     Alexei Starovoitov <ast@...nel.org>,
        Daniel Borkmann <daniel@...earbox.net>,
        netdev <netdev@...r.kernel.org>, Peter Oskolkov <posk@...k.io>,
        Willem de Bruijn <willemb@...gle.com>
Subject: Re: [PATCH bpf-next v10 5/7] bpf: add handling of BPF_LWT_REROUTE to lwt_bpf.c

On Wed, Feb 13, 2019 at 12:11 PM David Ahern <dsahern@...il.com> wrote:
>
> On 2/13/19 12:57 PM, Peter Oskolkov wrote:
> > Thanks, David! I was not able to reproduce the leak, but based on your
> > suggestion and similar code elsewhere I made a change in v11 to explicitly
> > release a dst with error.
>
> ok. Did you run the test with a debug kernel - checking refcount, use
> after free, etc?

In my tests I was always getting ERR_PTR for unroutable packets,
not a full rt/dst with an error flag set. But I checked several
similar route lookups,
and they all release bad dsts, so I did not feel it was worth it to
investigate further.