diff options
| author | Eric Dumazet <edumazet@google.com> | 2019-04-01 03:09:20 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2019-04-01 10:21:21 -0700 |
| commit | f5d547676ca068e10934687f59ac1e798eaae87a (patch) | |
| tree | 9c77da7b0c94136ad6eff3f19a0a289f3b7430df /net/ipv6 | |
| parent | 6578229d4efb7ea6287861bfc2bd306140458e07 (diff) | |
| download | linux-f5d547676ca068e10934687f59ac1e798eaae87a.tar.bz2 | |
tcp: fix tcp_inet6_sk() for 32bit kernels
It turns out that struct ipv6_pinfo is not located as we think.
inet6_sk_generic() and tcp_inet6_sk() disagree on 32bit kernels by 4-bytes,
because struct tcp_sock has 8-bytes alignment,
but ipv6_pinfo size is not a multiple of 8.
sizeof(struct ipv6_pinfo): 116 (not padded to 8)
I actually first coded tcp_inet6_sk() as this patch does, but thought
that "container_of(tcp_sk(sk), struct tcp6_sock, tcp)" was cleaner.
As Julian told me : Nobody should use tcp6_sock.inet6
directly, it should be accessed via tcp_inet6_sk() or inet6_sk().
This happened when we added the first u64 field in struct tcp_sock.
Fixes: 93a77c11ae79 ("tcp: add tcp_inet6_sk() helper")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Bisected-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv6')
| -rw-r--r-- | net/ipv6/tcp_ipv6.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c index eec814fe53b8..82018bdce863 100644 --- a/net/ipv6/tcp_ipv6.c +++ b/net/ipv6/tcp_ipv6.c @@ -93,12 +93,13 @@ static struct tcp_md5sig_key *tcp_v6_md5_do_lookup(const struct sock *sk, /* Helper returning the inet6 address from a given tcp socket. * It can be used in TCP stack instead of inet6_sk(sk). * This avoids a dereference and allow compiler optimizations. + * It is a specialized version of inet6_sk_generic(). */ static struct ipv6_pinfo *tcp_inet6_sk(const struct sock *sk) { - struct tcp6_sock *tcp6 = container_of(tcp_sk(sk), struct tcp6_sock, tcp); + unsigned int offset = sizeof(struct tcp6_sock) - sizeof(struct ipv6_pinfo); - return &tcp6->inet6; + return (struct ipv6_pinfo *)(((u8 *)sk) + offset); } static void inet6_sk_rx_dst_set(struct sock *sk, const struct sk_buff *skb) |