Re: [PATCH] net: rtnl: avoid uninitialized data in IFLA_VF_VLAN_LIST handling

[David Miller]

From: Arnd Bergmann <arnd@xxxxxxxx>
Date: Fri, 30 Sep 2016 18:13:49 +0200

> With the newly added support for IFLA_VF_VLAN_LIST netlink messages,
> we get a warning about potential uninitialized variable use in
> the parsing of the user input when enabling the -Wmaybe-uninitialized
> warning:
> 
> net/core/rtnetlink.c: In function 'do_setvfinfo':
> net/core/rtnetlink.c:1756:9: error: 'ivvl$' may be used uninitialized in this function [-Werror=maybe-uninitialized]
> 
> I have not been able to prove whether it is possible to arrive in
> this code with an empty IFLA_VF_VLAN_LIST block, but if we do,
> then ndo_set_vf_vlan gets called with uninitialized arguments.
> 
> This adds an explicit check for an empty list, making it obvious
> to the reader and the compiler that this cannot happen.
> 
> Fixes: 79aab093a0b5 ("net: Update API for VF vlan protocol 802.1ad support")
> Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>

Applied, thanks.