bpf/cpumap: make sure frame_size for build_skb is aligned if headroom isn't
The frame_size passed to build_skb must be aligned, else it is possible that the embedded struct skb_shared_info gets unaligned. For correctness make sure that xdpf->headroom in included in the alignment. No upstream drivers can hit this, as all XDP drivers provide an aligned headroom. This was discovered when playing with implementing XDP support for mvneta, which have a 2 bytes DSA header, and this Marvell ARM64 platform didn't like doing atomic operations on an unaligned skb_shinfo(skb)->dataref addresses. Fixes: 1c601d82 ("bpf: cpumap xdp_buff to skb conversion and allocation") Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
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