Commits
Florian Westphal committed 6e568307768
atl1c: reserve min skb headroom
Got crash report with following backtrace:
BUG: unable to handle kernel paging request at ffff8801869daffe
RIP: 0010:[<ffffffff816429c4>] [<ffffffff816429c4>] ip6_finish_output2+0x394/0x4c0
RSP: 0018:ffff880186c83a98 EFLAGS: 00010283
RAX: ffff8801869db00e ...
[<ffffffff81644cdc>] ip6_finish_output+0x8c/0xf0
[<ffffffff81644d97>] ip6_output+0x57/0x100
[<ffffffff81643dc9>] ip6_forward+0x4b9/0x840
[<ffffffff81645566>] ip6_rcv_finish+0x66/0xc0
[<ffffffff81645db9>] ipv6_rcv+0x319/0x530
[<ffffffff815892ac>] netif_receive_skb+0x1c/0x70
[<ffffffffc0060bec>] atl1c_clean+0x1ec/0x310 [atl1c]
...
The bad access is in neigh_hh_output(), at skb->data - 16 (HH_DATA_MOD).
atl1c driver provided skb with no headroom, so 14 bytes (ethernet
header) got pulled, but then 16 are copied.
Reserve NET_SKB_PAD bytes headroom, like netdev_alloc_skb().
Compile tested only; I lack hardware.
Fixes: 7b7017642199 ("atl1c: Fix misuse of netdev_alloc_skb in refilling rx ring")
Signed-off-by: Florian Westphal <fw@strlen.de>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>