v4.14-rc3/arm64 DABT exception in atomic_inc() / __skb_clone()

[Eric Dumazet]

On Wed, Oct 25, 2017 at 11:49 AM, Willem de Bruijn
<willemdebruijn.kernel at gmail.com> wrote:

> 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.

+1

Bug added in commit 66ccbc9c87c2 ("tap: use build_skb() for small packet")