From: Willem de Bruijn > Sent: 25 October 2017 19:50 ... > From skb->dev and netdev_priv, the tun device has flags 0x1002 == > IFF_TAP | IFF_NO_PI. This kernel precedes the recent support for > IFF_NAPI and IFF_NAPI_FRAGS. The allocation most likely happened > in tun_build_skb from current->task_frag. It would be a previous > allocation that left alloc_frag->offset unaligned. But perhaps this code > needs to perform alignment before setting skb->head. > > At least on platforms where atomic on dataref must be aligned.
Isn't that true of almost everything? I'm not even sure x86 always (ever?) manages locked cycles on misaligned addresses. David