[<prev] [next>] [<thread-prev] [day] [month] [year] [list]
Message-ID: <Z9tWZPaidMB4uvQu@pop-os.localdomain>
Date: Wed, 19 Mar 2025 16:42:28 -0700
From: Cong Wang <xiyou.wangcong@...il.com>
To: Dong Chenchen <dongchenchen2@...wei.com>
Cc: edumazet@...gle.com, kuniyu@...zon.com, pabeni@...hat.com,
willemb@...gle.com, john.fastabend@...il.com, jakub@...udflare.com,
davem@...emloft.net, kuba@...nel.org, horms@...nel.org,
daniel@...earbox.net, netdev@...r.kernel.org, bpf@...r.kernel.org,
stfomichev@...il.com, mrpre@....com, zhangchangzhong@...wei.com,
weiyongjun1@...wei.com
Subject: Re: [PATCH net 1/2] bpf, sockmap: Avoid sk_prot reset on sockmap
unlink with ULP set
On Fri, Mar 14, 2025 at 04:20:03PM +0800, Dong Chenchen wrote:
> WARNING: CPU: 0 PID: 6558 at net/core/sock_map.c:1703 sock_map_close+0x3c4/0x480
> Modules linked in:
> CPU: 0 UID: 0 PID: 6558 Comm: syz-executor.14 Not tainted 6.14.0-rc5+ #238
> RIP: 0010:sock_map_close+0x3c4/0x480
> Call Trace:
> <TASK>
> inet_release+0x144/0x280
> __sock_release+0xb8/0x270
> sock_close+0x1e/0x30
> __fput+0x3c6/0xb30
> __fput_sync+0x7b/0x90
> __x64_sys_close+0x90/0x120
> do_syscall_64+0x5d/0x170
> entry_SYSCALL_64_after_hwframe+0x76/0x7e
>
> The root cause is:
> bpf_prog_attach(BPF_SK_SKB_STREAM_VERDICT)
> tcp_set_ulp //set ulp after sockmap add
> icsk->icsk_ulp_ops = ulp_ops;
> sock_hash_update_common
> sock_map_unref
> sock_map_del_link
> psock->psock_update_sk_prot(sk, psock, false);
> sk->sk_prot->close = sock_map_close
> sk_psock_drop
> sk_psock_restore_proto
> tcp_bpf_update_proto
> tls_update //not redo sk_prot to tcp prot
> inet_release
> sk->sk_prot->close
> sock_map_close
> WARN(sk->sk_prot->close == sock_map_close)
This makes sense now. Please see my comment below.
>
> commit e34a07c0ae39 ("sock: redo the psock vs ULP protection check")
> has moved ulp check from tcp_bpf_update_proto() to psock init.
> If sk sets ulp after being added to sockmap, it will reset sk_prot to
> BPF_BASE when removed from sockmap. After the psock is dropped, it will
> not reset sk_prot back to the tcp prot, only tls context update is
> performed. This can trigger a warning in sock_map_close() due to
> recursion of sk->sk_prot->close.
>
> To fix this issue, skip the sk_prot operations redo when deleting link
> from sockmap if ULP is set.
>
> Fixes: e34a07c0ae39 ("sock: redo the psock vs ULP protection check")
> Fixes: c0d95d3380ee ("bpf, sockmap: Re-evaluate proto ops when psock is removed from sockmap")
> Signed-off-by: Dong Chenchen <dongchenchen2@...wei.com>
> ---
> net/core/sock_map.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/net/core/sock_map.c b/net/core/sock_map.c
> index 82a14f131d00..a3ed1f2cf8a2 100644
> --- a/net/core/sock_map.c
> +++ b/net/core/sock_map.c
> @@ -170,7 +170,7 @@ static void sock_map_del_link(struct sock *sk,
> if (verdict_stop)
> sk_psock_stop_verdict(sk, psock);
>
> - if (psock->psock_update_sk_prot)
> + if (!(sk_is_inet(sk) && inet_csk_has_ulp(sk)) && psock->psock_update_sk_prot)
> psock->psock_update_sk_prot(sk, psock, false);
Can we put this TCP-specific logic into tcp_bpf_update_proto() instead?
Something like this...
diff --git a/net/ipv4/tcp_bpf.c b/net/ipv4/tcp_bpf.c
index ba581785adb4..0bb363447fc7 100644
--- a/net/ipv4/tcp_bpf.c
+++ b/net/ipv4/tcp_bpf.c
@@ -708,6 +708,8 @@ int tcp_bpf_update_proto(struct sock *sk, struct sk_psock *psock, bool restore)
return 0;
}
+ if (inet_csk_has_ulp(sk))
+ return 0;
if (sk->sk_family == AF_INET6) {
if (tcp_bpf_assert_proto_ops(psock->sk_proto))
return -EINVAL;
Powered by blists - more mailing lists