[PATCH net-next v3 0/2] tcp: add tcp_warn_once() common helper

[PATCH net-next v3 0/2] tcp: add tcp_warn_once() common helper

[Jason Xing]

From: Jason Xing <kernelxing@tencent.com>

Paolo Abeni suggested we can introduce a new helper to cover more cases
in the future for better debug.

Jason Xing (2):
  tcp: add a common helper to debug the underlying issue
  tcp: add more warn of socket in tcp_send_loss_probe()

 include/net/tcp.h     | 26 +++++++++++++++-----------
 net/ipv4/tcp_output.c |  4 +---
 2 files changed, 16 insertions(+), 14 deletions(-)

-- 
2.37.3

[PATCH net-next v3 1/2] tcp: add a common helper to debug the underlying issue

[Jason Xing]

From: Jason Xing <kernelxing@tencent.com>

Following the commit c8770db2d544 ("tcp: check skb is non-NULL
in tcp_rto_delta_us()"), we decided to add a helper so that it's
easier to get verbose warning on either cases.

Link: https://lore.kernel.org/all/5632e043-bdba-4d75-bc7e-bf58014492fd@redhat.com/
Suggested-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Jason Xing <kernelxing@tencent.com>
Cc: Neal Cardwell <ncardwell@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
---
v3
Link: https://lore.kernel.org/all/f6e70c8d-b9d8-4d15-bb25-69fbec0d138a@kernel.org/
1. add reviewed-by tag (David)

v2
Link: https://lore.kernel.org/all/38811a75-ae98-48e7-96c0-bb1a39a0d722@kernel.org/
1. fix "break quoted strings at a space character" warning (David Ahern)
---
 include/net/tcp.h | 25 ++++++++++++++-----------
 1 file changed, 14 insertions(+), 11 deletions(-)

diff --git a/include/net/tcp.h b/include/net/tcp.h
index 739a9fb83d0c..8b8d94bb1746 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -2430,6 +2430,19 @@ void tcp_plb_update_state(const struct sock *sk, struct tcp_plb_state *plb,
 void tcp_plb_check_rehash(struct sock *sk, struct tcp_plb_state *plb);
 void tcp_plb_update_state_upon_rto(struct sock *sk, struct tcp_plb_state *plb);
 
+static inline void tcp_warn_once(const struct sock *sk, bool cond, const char *str)
+{
+	WARN_ONCE(cond,
+		  "%sout:%u sacked:%u lost:%u retrans:%u tlp_high_seq:%u sk_state:%u ca_state:%u advmss:%u mss_cache:%u pmtu:%u\n",
+		  str,
+		  tcp_sk(sk)->packets_out, tcp_sk(sk)->sacked_out,
+		  tcp_sk(sk)->lost_out, tcp_sk(sk)->retrans_out,
+		  tcp_sk(sk)->tlp_high_seq, sk->sk_state,
+		  inet_csk(sk)->icsk_ca_state,
+		  tcp_sk(sk)->advmss, tcp_sk(sk)->mss_cache,
+		  inet_csk(sk)->icsk_pmtu_cookie);
+}
+
 /* At how many usecs into the future should the RTO fire? */
 static inline s64 tcp_rto_delta_us(const struct sock *sk)
 {
@@ -2441,17 +2454,7 @@ static inline s64 tcp_rto_delta_us(const struct sock *sk)
 
 		return rto_time_stamp_us - tcp_sk(sk)->tcp_mstamp;
 	} else {
-		WARN_ONCE(1,
-			"rtx queue empty: "
-			"out:%u sacked:%u lost:%u retrans:%u "
-			"tlp_high_seq:%u sk_state:%u ca_state:%u "
-			"advmss:%u mss_cache:%u pmtu:%u\n",
-			tcp_sk(sk)->packets_out, tcp_sk(sk)->sacked_out,
-			tcp_sk(sk)->lost_out, tcp_sk(sk)->retrans_out,
-			tcp_sk(sk)->tlp_high_seq, sk->sk_state,
-			inet_csk(sk)->icsk_ca_state,
-			tcp_sk(sk)->advmss, tcp_sk(sk)->mss_cache,
-			inet_csk(sk)->icsk_pmtu_cookie);
+		tcp_warn_once(sk, 1, "rtx queue empty: ");
 		return jiffies_to_usecs(rto);
 	}
 
-- 
2.37.3

[PATCH net-next v3 2/2] tcp: add more warn of socket in tcp_send_loss_probe()

[Jason Xing]

From: Jason Xing <kernelxing@tencent.com>

Add two fields to print in the helper which here covers tcp_send_loss_probe().

Link: https://lore.kernel.org/all/5632e043-bdba-4d75-bc7e-bf58014492fd@redhat.com/
Suggested-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Jason Xing <kernelxing@tencent.com>
Cc: Neal Cardwell <ncardwell@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
--
v3
Link: https://lore.kernel.org/all/20241021155245.83122-3-kerneljasonxing@gmail.com/
1. add missing string "invalid inflight: " (David)
2. add reviewed-by tag (David)
3. remove tcp_current_mss() due to possible change happening on the socket's state (Eric)

v2
Link:https://lore.kernel.org/all/CAL+tcoAr7RHhaZGV12wYDcPPPaubAqdxMCmy7Jujtr8b3+bY=w@mail.gmail.com/
1. use "" instead of NULL in tcp_send_loss_probe()
---
 include/net/tcp.h     | 3 ++-
 net/ipv4/tcp_output.c | 4 +---
 2 files changed, 3 insertions(+), 4 deletions(-)

diff --git a/include/net/tcp.h b/include/net/tcp.h
index 8b8d94bb1746..e9b37b76e894 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -2433,8 +2433,9 @@ void tcp_plb_update_state_upon_rto(struct sock *sk, struct tcp_plb_state *plb);
 static inline void tcp_warn_once(const struct sock *sk, bool cond, const char *str)
 {
 	WARN_ONCE(cond,
-		  "%sout:%u sacked:%u lost:%u retrans:%u tlp_high_seq:%u sk_state:%u ca_state:%u advmss:%u mss_cache:%u pmtu:%u\n",
+		  "%scwn:%u out:%u sacked:%u lost:%u retrans:%u tlp_high_seq:%u sk_state:%u ca_state:%u advmss:%u mss_cache:%u pmtu:%u\n",
 		  str,
+		  tcp_snd_cwnd(tcp_sk(sk)),
 		  tcp_sk(sk)->packets_out, tcp_sk(sk)->sacked_out,
 		  tcp_sk(sk)->lost_out, tcp_sk(sk)->retrans_out,
 		  tcp_sk(sk)->tlp_high_seq, sk->sk_state,
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index 054244ce5117..5485a70b5fe5 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -2954,9 +2954,7 @@ void tcp_send_loss_probe(struct sock *sk)
 	}
 	skb = skb_rb_last(&sk->tcp_rtx_queue);
 	if (unlikely(!skb)) {
-		WARN_ONCE(tp->packets_out,
-			  "invalid inflight: %u state %u cwnd %u mss %d\n",
-			  tp->packets_out, sk->sk_state, tcp_snd_cwnd(tp), mss);
+		tcp_warn_once(sk, tp->packets_out, "invalid inflight: ");
 		smp_store_release(&inet_csk(sk)->icsk_pending, 0);
 		return;
 	}
-- 
2.37.3

Re: [PATCH net-next v3 0/2] tcp: add tcp_warn_once() common helper

[patchwork-bot+netdevbpf]

Hello:

This series was applied to netdev/net-next.git (main)
by David S. Miller <davem@davemloft.net>:

On Wed, 23 Oct 2024 16:14:50 +0800 you wrote:
> From: Jason Xing <kernelxing@tencent.com>
> 
> Paolo Abeni suggested we can introduce a new helper to cover more cases
> in the future for better debug.
> 
> Jason Xing (2):
>   tcp: add a common helper to debug the underlying issue
>   tcp: add more warn of socket in tcp_send_loss_probe()
> 
> [...]

Here is the summary with links:
  - [net-next,v3,1/2] tcp: add a common helper to debug the underlying issue
    https://git.kernel.org/netdev/net-next/c/386c2b877b97
  - [net-next,v3,2/2] tcp: add more warn of socket in tcp_send_loss_probe()
    https://git.kernel.org/netdev/net-next/c/668d663989c7

You are awesome, thank you!
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