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 Stable-dep-of: 8bbabb3fddcd ("bpf, sock_map: Move cancel_work_sync() out of sock lock") Signed-off-by: Sasha Levin sashal@kernel.org [Conflict in include/linux/bpf.h due to function declaration position and remove non-existed sk_psock_stop helper from sock_map_destroy.] Signed-off-by: Wen Gu guwen@linux.alibaba.com --- background: Link: https://lore.kernel.org/stable/d11bc7e6-a2c7-445a-8561-3599eafb07b0@linux.al...

@stable team: This backport has 2 changes compared to the original patch: - fix conflict due to sock_map_destroy declaration position in include/linux/bpf.h; - remove the non-existed sk_psock_stop helper from sock_map_destroy. This helper is introduced by 799aa7f98d53 ("skmsg: Avoid lock_sock() in sk_psock_backlog()") after v5.10, it is not a fix and hard to backport. Considering that what did in sk_psock_stop is done in sk_psock_drop and neither sock_map_close nor sock_map_unhash in v5.10 introduces sk_psock_stop, I removed it from sock_map_destroy too. I tested it in my environment, the regression was gone.

Cc: Wang Yufen wangyufen@huawei.com @Yufen, if I missed anything, please point it out, thanks! --- include/linux/bpf.h | 1 + include/linux/skmsg.h | 1 + net/core/skmsg.c | 1 + net/core/sock_map.c | 22 ++++++++++++++++++++++ net/ipv4/tcp_bpf.c | 1 + 5 files changed, 26 insertions(+)

diff --git a/include/linux/bpf.h b/include/linux/bpf.h index a75faf437e75..340f4fef5b5a 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -1800,6 +1800,7 @@ 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 sock_map_prog_update(struct bpf_map *map, diff --git a/include/linux/skmsg.h b/include/linux/skmsg.h index 1138dd3071db..e2af013ec05f 100644 --- a/include/linux/skmsg.h +++ b/include/linux/skmsg.h @@ -98,6 +98,7 @@ 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); struct proto *sk_proto; diff --git a/net/core/skmsg.c b/net/core/skmsg.c index bb4fbc60b272..51792dda1b73 100644 --- a/net/core/skmsg.c +++ b/net/core/skmsg.c @@ -599,6 +599,7 @@ 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 52e395a189df..d1d0ee2dbfaa 100644 --- a/net/core/sock_map.c +++ b/net/core/sock_map.c @@ -1566,6 +1566,28 @@ void sock_map_unhash(struct sock *sk) saved_unhash(sk); }

+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_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 d0ca1fc325cd..f909e440bb22 100644 --- a/net/ipv4/tcp_bpf.c +++ b/net/ipv4/tcp_bpf.c @@ -582,6 +582,7 @@ 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].stream_memory_read = tcp_bpf_stream_read;