This fixes some corner cases triggered by enabling fraglist GRO, where some
protocols may accidentally or intentionally linearize fraglist skbs.
Previously, these skbs became unusable and segmenting them led to crashes.
With this patch, they are properly handled by passing them to skb_segment
instead of skb_segment_list.
Signed-off-by: Felix Fietkau <nbd@nbd.name>
