From: Wang Yufen wangyufen@huawei.com
[ Upstream commit 84472b436e760ba439e1969a9e3c5ae7c86de39d ]
In tcp_bpf_send_verdict(), if msg has more data after tcp_bpf_sendmsg_redir():
tcp_bpf_send_verdict() tosend = msg->sg.size //msg->sg.size = 22220 case __SK_REDIRECT: sk_msg_return() //uncharged msg->sg.size(22220) sk->sk_forward_alloc tcp_bpf_sendmsg_redir() //after tcp_bpf_sendmsg_redir, msg->sg.size=11000 goto more_data; tosend = msg->sg.size //msg->sg.size = 11000 case __SK_REDIRECT: sk_msg_return() //uncharged msg->sg.size(11000) to sk->sk_forward_alloc
The msg->sg.size(11000) has been uncharged twice, to fix we can charge the remaining msg->sg.size before goto more data.
This issue can cause the following info: WARNING: CPU: 0 PID: 9860 at net/core/stream.c:208 sk_stream_kill_queues+0xd4/0x1a0 Call Trace: <TASK> inet_csk_destroy_sock+0x55/0x110 __tcp_close+0x279/0x470 tcp_close+0x1f/0x60 inet_release+0x3f/0x80 __sock_release+0x3d/0xb0 sock_close+0x11/0x20 __fput+0x92/0x250 task_work_run+0x6a/0xa0 do_exit+0x33b/0xb60 do_group_exit+0x2f/0xa0 get_signal+0xb6/0x950 arch_do_signal_or_restart+0xac/0x2a0 ? vfs_write+0x237/0x290 exit_to_user_mode_prepare+0xa9/0x200 syscall_exit_to_user_mode+0x12/0x30 do_syscall_64+0x46/0x80 entry_SYSCALL_64_after_hwframe+0x44/0xae </TASK>
WARNING: CPU: 0 PID: 2136 at net/ipv4/af_inet.c:155 inet_sock_destruct+0x13c/0x260 Call Trace: <TASK> __sk_destruct+0x24/0x1f0 sk_psock_destroy+0x19b/0x1c0 process_one_work+0x1b3/0x3c0 worker_thread+0x30/0x350 ? process_one_work+0x3c0/0x3c0 kthread+0xe6/0x110 ? kthread_complete_and_exit+0x20/0x20 ret_from_fork+0x22/0x30 </TASK>
Fixes: 604326b41a6f ("bpf, sockmap: convert to generic sk_msg interface") Signed-off-by: Wang Yufen wangyufen@huawei.com Signed-off-by: Daniel Borkmann daniel@iogearbox.net Acked-by: John Fastabend john.fastabend@gmail.com Link: https://lore.kernel.org/bpf/20220304081145.2037182-4-wangyufen@huawei.com Signed-off-by: Sasha Levin sashal@kernel.org --- net/ipv4/tcp_bpf.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/net/ipv4/tcp_bpf.c b/net/ipv4/tcp_bpf.c index 7df7ec74807a..1584863bbdc1 100644 --- a/net/ipv4/tcp_bpf.c +++ b/net/ipv4/tcp_bpf.c @@ -367,7 +367,7 @@ static int tcp_bpf_send_verdict(struct sock *sk, struct sk_psock *psock, cork = true; psock->cork = NULL; } - sk_msg_return(sk, msg, tosend); + sk_msg_return(sk, msg, msg->sg.size); release_sock(sk);
ret = tcp_bpf_sendmsg_redir(sk_redir, msg, tosend, flags); @@ -407,8 +407,11 @@ static int tcp_bpf_send_verdict(struct sock *sk, struct sk_psock *psock, } if (msg && msg->sg.data[msg->sg.start].page_link && - msg->sg.data[msg->sg.start].length) + msg->sg.data[msg->sg.start].length) { + if (eval == __SK_REDIRECT) + sk_mem_charge(sk, msg->sg.size); goto more_data; + } } return ret; }