Re: [PATCH 2/2] mlxsw: spectrum_router: avoid potential uninitialized data usage

From: David Miller
Date: Mon Oct 03 2016 - 01:56:38 EST

From: Arnd Bergmann <arnd@xxxxxxxx>
Date: Fri, 30 Sep 2016 18:17:10 +0200

> If fi->fib_nhs is zero, the router interface pointer is uninitialized, as shown by
> this warning:
> drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c: In function 'mlxsw_sp_router_fib_event':
> drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c:1674:21: error: 'r' may be used uninitialized in this function [-Werror=maybe-uninitialized]
> drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c:1643:23: note: 'r' was declared here
> This changes the loop so we handle the case the same way as finding no router
> interface pointer attached to one of the nexthops to ensure we always
> trap here instead of using uninitialized data.
> Fixes: b45f64d16d45 ("mlxsw: spectrum_router: Use FIB notifications instead of switchdev calls")
> Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>