diff options
| author | Eric Dumazet <edumazet@google.com> | 2018-10-02 21:35:05 +0200 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2018-10-03 00:52:12 +0200 |
| commit | 2ab2ddd301a22ca3c5f0b743593e4ad2953dfa53 (patch) | |
| tree | 3ec72a50a6be78a4bc8eb73d8c9bd14df798aa26 /net/dccp | |
| parent | nfp: avoid soft lockups under control message storm (diff) | |
| download | linux-2ab2ddd301a22ca3c5f0b743593e4ad2953dfa53.tar.xz linux-2ab2ddd301a22ca3c5f0b743593e4ad2953dfa53.zip | |
inet: make sure to grab rcu_read_lock before using ireq->ireq_opt
Timer handlers do not imply rcu_read_lock(), so my recent fix
triggered a LOCKDEP warning when SYNACK is retransmit.
Lets add rcu_read_lock()/rcu_read_unlock() pairs around ireq->ireq_opt
usages instead of guessing what is done by callers, since it is
not worth the pain.
Get rid of ireq_opt_deref() helper since it hides the logic
without real benefit, since it is now a standard rcu_dereference().
Fixes: 1ad98e9d1bdf ("tcp/dccp: fix lockdep issue when SYN is backlogged")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/dccp')
| -rw-r--r-- | net/dccp/ipv4.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/net/dccp/ipv4.c b/net/dccp/ipv4.c index b08feb219b44..8e08cea6f178 100644 --- a/net/dccp/ipv4.c +++ b/net/dccp/ipv4.c @@ -493,9 +493,11 @@ static int dccp_v4_send_response(const struct sock *sk, struct request_sock *req dh->dccph_checksum = dccp_v4_csum_finish(skb, ireq->ir_loc_addr, ireq->ir_rmt_addr); + rcu_read_lock(); err = ip_build_and_send_pkt(skb, sk, ireq->ir_loc_addr, ireq->ir_rmt_addr, - ireq_opt_deref(ireq)); + rcu_dereference(ireq->ireq_opt)); + rcu_read_unlock(); err = net_xmit_eval(err); } |