From mboxrd@z Thu Jan  1 00:00:00 1970
From: David Miller <davem@davemloft.net>
Subject: Re: [PATCH net] net: always initialize pagedlen
Date: Sat, 24 Nov 2018 17:43:36 -0800 (PST)
Message-ID: <20181124.174336.2013396951281875471.davem@davemloft.net>
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From: Willem de Bruijn <willemdebruijn.kernel@gmail.com>
Date: Sat, 24 Nov 2018 14:21:16 -0500

> From: Willem de Bruijn <willemb@google.com>
> 
> In ip packet generation, pagedlen is initialized for each skb at the
> start of the loop in __ip(6)_append_data, before label alloc_new_skb.
> 
> Depending on compiler options, code can be generated that jumps to
> this label, triggering use of an an uninitialized variable.
> 
> In practice, at -O2, the generated code moves the initialization below
> the label. But the code should not rely on that for correctness.
> 
> Fixes: 15e36f5b8e98 ("udp: paged allocation with gso")
> Signed-off-by: Willem de Bruijn <willemb@google.com>
> 
> ---
> 
> Noticed when rebasing udp zerocopy. I considered merging as part of
> that patchset, but this seemed like it should go to net, even if it
> does not trigger in practice.
> 
> Merged net with this patch onto net-next with udp zerocopy to verify
> that there is no merge conflict.

Ok, applied, but not queued for -stable.

Let me know if I should -stable this.