From: Wang Yufen wangyufen@huawei.com
[ Upstream commit d8616ee2affcff37c5d315310da557a694a3303d ]
During TCP sockmap redirect pressure test, the following warning is triggered:
WARNING: CPU: 3 PID: 2145 at net/core/stream.c:205 sk_stream_kill_queues+0xbc/0xd0 CPU: 3 PID: 2145 Comm: iperf Kdump: loaded Tainted: G W 5.10.0+ #9 Call Trace: inet_csk_destroy_sock+0x55/0x110 inet_csk_listen_stop+0xbb/0x380 tcp_close+0x41b/0x480 inet_release+0x42/0x80 __sock_release+0x3d/0xa0 sock_close+0x11/0x20 __fput+0x9d/0x240 task_work_run+0x62/0x90 exit_to_user_mode_prepare+0x110/0x120 syscall_exit_to_user_mode+0x27/0x190 entry_SYSCALL_64_after_hwframe+0x44/0xa9
The reason we observed is that:
When the listener is closing, a connection may have completed the three-way handshake but not accepted, and the client has sent some packets. The child sks in accept queue release by inet_child_forget()->inet_csk_destroy_sock(), but psocks of child sks have not released.
To fix, add sock_map_destroy to release psocks.
Signed-off-by: Wang Yufen wangyufen@huawei.com Signed-off-by: Daniel Borkmann daniel@iogearbox.net Signed-off-by: Andrii Nakryiko andrii@kernel.org Acked-by: Jakub Sitnicki jakub@cloudflare.com Acked-by: John Fastabend john.fastabend@gmail.com Link: https://lore.kernel.org/bpf/20220524075311.649153-1-wangyufen@huawei.com Signed-off-by: Sasha Levin sashal@kernel.org --- include/linux/bpf.h | 1 + include/linux/skmsg.h | 1 + net/core/skmsg.c | 1 + net/core/sock_map.c | 23 +++++++++++++++++++++++ net/ipv4/tcp_bpf.c | 1 + 5 files changed, 27 insertions(+)
diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 818cd594e922..84efd8dd139d 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -2022,6 +2022,7 @@ int sock_map_get_from_fd(const union bpf_attr *attr, struct bpf_prog *prog); int sock_map_prog_detach(const union bpf_attr *attr, enum bpf_prog_type ptype); int sock_map_update_elem_sys(struct bpf_map *map, void *key, void *value, u64 flags); void sock_map_unhash(struct sock *sk); +void sock_map_destroy(struct sock *sk); void sock_map_close(struct sock *sk, long timeout); #else static inline int bpf_prog_offload_init(struct bpf_prog *prog, diff --git a/include/linux/skmsg.h b/include/linux/skmsg.h index 73bedd128d52..ad3b798d9944 100644 --- a/include/linux/skmsg.h +++ b/include/linux/skmsg.h @@ -96,6 +96,7 @@ struct sk_psock { spinlock_t link_lock; refcount_t refcnt; void (*saved_unhash)(struct sock *sk); + void (*saved_destroy)(struct sock *sk); void (*saved_close)(struct sock *sk, long timeout); void (*saved_write_space)(struct sock *sk); void (*saved_data_ready)(struct sock *sk); diff --git a/net/core/skmsg.c b/net/core/skmsg.c index ede0af308f40..2742d8e4dd82 100644 --- a/net/core/skmsg.c +++ b/net/core/skmsg.c @@ -716,6 +716,7 @@ struct sk_psock *sk_psock_init(struct sock *sk, int node) psock->eval = __SK_NONE; psock->sk_proto = prot; psock->saved_unhash = prot->unhash; + psock->saved_destroy = prot->destroy; psock->saved_close = prot->close; psock->saved_write_space = sk->sk_write_space;
diff --git a/net/core/sock_map.c b/net/core/sock_map.c index 6351b6af7aca..d846ed9c5855 100644 --- a/net/core/sock_map.c +++ b/net/core/sock_map.c @@ -1506,6 +1506,29 @@ void sock_map_unhash(struct sock *sk) } EXPORT_SYMBOL_GPL(sock_map_unhash);
+void sock_map_destroy(struct sock *sk) +{ + void (*saved_destroy)(struct sock *sk); + struct sk_psock *psock; + + rcu_read_lock(); + psock = sk_psock_get(sk); + if (unlikely(!psock)) { + rcu_read_unlock(); + if (sk->sk_prot->destroy) + sk->sk_prot->destroy(sk); + return; + } + + saved_destroy = psock->saved_destroy; + sock_map_remove_links(sk, psock); + rcu_read_unlock(); + sk_psock_stop(psock, true); + sk_psock_put(sk, psock); + saved_destroy(sk); +} +EXPORT_SYMBOL_GPL(sock_map_destroy); + void sock_map_close(struct sock *sk, long timeout) { void (*saved_close)(struct sock *sk, long timeout); diff --git a/net/ipv4/tcp_bpf.c b/net/ipv4/tcp_bpf.c index 2c597a4e429a..25e83d35138b 100644 --- a/net/ipv4/tcp_bpf.c +++ b/net/ipv4/tcp_bpf.c @@ -541,6 +541,7 @@ static void tcp_bpf_rebuild_protos(struct proto prot[TCP_BPF_NUM_CFGS], struct proto *base) { prot[TCP_BPF_BASE] = *base; + prot[TCP_BPF_BASE].destroy = sock_map_destroy; prot[TCP_BPF_BASE].close = sock_map_close; prot[TCP_BPF_BASE].recvmsg = tcp_bpf_recvmsg; prot[TCP_BPF_BASE].sock_is_readable = sk_msg_is_readable;