Re: [PATCH] flow_dissector: Pre-initialize ip_proto in __skb_flow_dissect()

[David Miller]

From: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
Date: Thu, 25 Jun 2015 15:10:32 +0200

> net/core/flow_dissector.c: In function ʽ__skb_flow_dissectʼ:
> net/core/flow_dissector.c:132: warning: ʽip_protoʼ may be used uninitialized in this function
> 
> Signed-off-by: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
> ---
> This may be a false positive, but the state machine in
> __skb_flow_dissect() is a bit hard to follow.
> As I believe it is controlled by a packet received from the network, the
> only safe thing to do is to pre-initialize ip_proto.

Actually I think this is a real bug, because for the ETH_P_MPLS_* cases I cannot
see what will always set ip_proto before it gets used as an input.