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authorEric Dumazet <edumazet@google.com>2016-02-18 16:39:18 +0300
committerDavid S. Miller <davem@davemloft.net>2016-02-18 19:35:51 +0300
commit7716682cc58e305e22207d5bb315f26af6b1e243 (patch)
treebd3b7c897a192192bf0312cca7f4cd0e5f39da5d /include/net
parentdeed49df7390d5239024199e249190328f1651e7 (diff)
downloadlinux-7716682cc58e305e22207d5bb315f26af6b1e243.tar.xz
tcp/dccp: fix another race at listener dismantle
Ilya reported following lockdep splat: kernel: ========================= kernel: [ BUG: held lock freed! ] kernel: 4.5.0-rc1-ceph-00026-g5e0a311 #1 Not tainted kernel: ------------------------- kernel: swapper/5/0 is freeing memory ffff880035c9d200-ffff880035c9dbff, with a lock still held there! kernel: (&(&queue->rskq_lock)->rlock){+.-...}, at: [<ffffffff816f6a88>] inet_csk_reqsk_queue_add+0x28/0xa0 kernel: 4 locks held by swapper/5/0: kernel: #0: (rcu_read_lock){......}, at: [<ffffffff8169ef6b>] netif_receive_skb_internal+0x4b/0x1f0 kernel: #1: (rcu_read_lock){......}, at: [<ffffffff816e977f>] ip_local_deliver_finish+0x3f/0x380 kernel: #2: (slock-AF_INET){+.-...}, at: [<ffffffff81685ffb>] sk_clone_lock+0x19b/0x440 kernel: #3: (&(&queue->rskq_lock)->rlock){+.-...}, at: [<ffffffff816f6a88>] inet_csk_reqsk_queue_add+0x28/0xa0 To properly fix this issue, inet_csk_reqsk_queue_add() needs to return to its callers if the child as been queued into accept queue. We also need to make sure listener is still there before calling sk->sk_data_ready(), by holding a reference on it, since the reference carried by the child can disappear as soon as the child is put on accept queue. Reported-by: Ilya Dryomov <idryomov@gmail.com> Fixes: ebb516af60e1 ("tcp/dccp: fix race at listener dismantle phase") Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/net')
-rw-r--r--include/net/inet_connection_sock.h5
1 files changed, 3 insertions, 2 deletions
diff --git a/include/net/inet_connection_sock.h b/include/net/inet_connection_sock.h
index 481fe1c9044c..49dcad4fe99e 100644
--- a/include/net/inet_connection_sock.h
+++ b/include/net/inet_connection_sock.h
@@ -270,8 +270,9 @@ struct dst_entry *inet_csk_route_child_sock(const struct sock *sk,
struct sock *newsk,
const struct request_sock *req);
-void inet_csk_reqsk_queue_add(struct sock *sk, struct request_sock *req,
- struct sock *child);
+struct sock *inet_csk_reqsk_queue_add(struct sock *sk,
+ struct request_sock *req,
+ struct sock *child);
void inet_csk_reqsk_queue_hash_add(struct sock *sk, struct request_sock *req,
unsigned long timeout);
struct sock *inet_csk_complete_hashdance(struct sock *sk, struct sock *child,