* [PATCH v2 net-next] tcp: socket-specific version of WARN_ON_ONCE()
@ 2022-12-08 15:46 Breno Leitao
2022-12-09 7:55 ` Kuniyuki Iwashima
2022-12-11 8:44 ` Sven Schnelle
0 siblings, 2 replies; 3+ messages in thread
From: Breno Leitao @ 2022-12-08 15:46 UTC (permalink / raw)
To: edumazet, davem, kuba, pabeni, kuniyu
Cc: netdev, leit, yoshfuji, dsahern, linux-kernel
There are cases where we need relevant information about the socket
during a warning, so, it could help us to find bugs that happens and do
not have an easy repro.
This patch creates a TCP-socket specific version of WARN_ON_ONCE(), which
dumps revelant information about the TCP socket when it hits rare
warnings, which is super useful for debugging purposes.
Hooking this warning tcp_snd_cwnd_set() for now, but, the intent is to
convert more TCP warnings to this helper later.
Signed-off-by: Breno Leitao <leitao@debian.org>
---
include/net/tcp.h | 3 ++-
include/net/tcp_debug.h | 10 ++++++++++
net/ipv4/tcp.c | 30 ++++++++++++++++++++++++++++++
3 files changed, 42 insertions(+), 1 deletion(-)
create mode 100644 include/net/tcp_debug.h
diff --git a/include/net/tcp.h b/include/net/tcp.h
index 14d45661a84d..e490af8e6fdc 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -40,6 +40,7 @@
#include <net/inet_ecn.h>
#include <net/dst.h>
#include <net/mptcp.h>
+#include <net/tcp_debug.h>
#include <linux/seq_file.h>
#include <linux/memcontrol.h>
@@ -1229,7 +1230,7 @@ static inline u32 tcp_snd_cwnd(const struct tcp_sock *tp)
static inline void tcp_snd_cwnd_set(struct tcp_sock *tp, u32 val)
{
- WARN_ON_ONCE((int)val <= 0);
+ TCP_SOCK_WARN_ON_ONCE(tp, (int)val <= 0);
tp->snd_cwnd = val;
}
diff --git a/include/net/tcp_debug.h b/include/net/tcp_debug.h
new file mode 100644
index 000000000000..50e96d87d335
--- /dev/null
+++ b/include/net/tcp_debug.h
@@ -0,0 +1,10 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_TCP_DEBUG_H
+#define _LINUX_TCP_DEBUG_H
+
+void tcp_sock_warn(const struct tcp_sock *tp);
+
+#define TCP_SOCK_WARN_ON_ONCE(tcp_sock, condition) \
+ DO_ONCE_LITE_IF(condition, tcp_sock_warn, tcp_sock)
+
+#endif /* _LINUX_TCP_DEBUG_H */
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 54836a6b81d6..5985ba9c4231 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -4705,6 +4705,36 @@ int tcp_abort(struct sock *sk, int err)
}
EXPORT_SYMBOL_GPL(tcp_abort);
+void tcp_sock_warn(const struct tcp_sock *tp)
+{
+ const struct sock *sk = (const struct sock *)tp;
+ struct inet_sock *inet = inet_sk(sk);
+ struct inet_connection_sock *icsk = inet_csk(sk);
+
+ WARN_ON(1);
+
+ pr_warn("Socket Info: family=%u state=%d ccname=%s cwnd=%u",
+ sk->sk_family, sk->sk_state, icsk->icsk_ca_ops->name,
+ tcp_snd_cwnd(tp));
+
+ switch (sk->sk_family) {
+ case AF_INET:
+ pr_warn("saddr=%pI4:%u daddr=%pI4:%u", &inet->inet_saddr,
+ ntohs(inet->inet_sport), &inet->inet_daddr,
+ ntohs(inet->inet_dport));
+
+ break;
+#if IS_ENABLED(CONFIG_IPV6)
+ case AF_INET6:
+ pr_warn("saddr=[%pI6]:%u daddr=[%pI6]:%u", &sk->sk_v6_rcv_saddr,
+ ntohs(inet->inet_sport), &sk->sk_v6_daddr,
+ ntohs(inet->inet_dport));
+ break;
+#endif
+ }
+}
+EXPORT_SYMBOL_GPL(tcp_sock_warn);
+
extern struct tcp_congestion_ops tcp_reno;
static __initdata unsigned long thash_entries;
--
2.30.2
^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [PATCH v2 net-next] tcp: socket-specific version of WARN_ON_ONCE()
2022-12-08 15:46 [PATCH v2 net-next] tcp: socket-specific version of WARN_ON_ONCE() Breno Leitao
@ 2022-12-09 7:55 ` Kuniyuki Iwashima
2022-12-11 8:44 ` Sven Schnelle
1 sibling, 0 replies; 3+ messages in thread
From: Kuniyuki Iwashima @ 2022-12-09 7:55 UTC (permalink / raw)
To: leitao
Cc: davem, dsahern, edumazet, kuba, kuniyu, leit, linux-kernel,
netdev, pabeni, yoshfuji
From: Breno Leitao <leitao@debian.org>
Date: Thu, 8 Dec 2022 07:46:56 -0800
> There are cases where we need relevant information about the socket
> during a warning, so, it could help us to find bugs that happens and do
> not have an easy repro.
>
> This patch creates a TCP-socket specific version of WARN_ON_ONCE(), which
> dumps revelant information about the TCP socket when it hits rare
> warnings, which is super useful for debugging purposes.
>
> Hooking this warning tcp_snd_cwnd_set() for now, but, the intent is to
> convert more TCP warnings to this helper later.
>
> Signed-off-by: Breno Leitao <leitao@debian.org>
Acked-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Looks good to me, thank you.
A minor comment below.
> ---
> include/net/tcp.h | 3 ++-
> include/net/tcp_debug.h | 10 ++++++++++
> net/ipv4/tcp.c | 30 ++++++++++++++++++++++++++++++
> 3 files changed, 42 insertions(+), 1 deletion(-)
> create mode 100644 include/net/tcp_debug.h
>
> diff --git a/include/net/tcp.h b/include/net/tcp.h
> index 14d45661a84d..e490af8e6fdc 100644
> --- a/include/net/tcp.h
> +++ b/include/net/tcp.h
> @@ -40,6 +40,7 @@
> #include <net/inet_ecn.h>
> #include <net/dst.h>
> #include <net/mptcp.h>
> +#include <net/tcp_debug.h>
>
> #include <linux/seq_file.h>
> #include <linux/memcontrol.h>
> @@ -1229,7 +1230,7 @@ static inline u32 tcp_snd_cwnd(const struct tcp_sock *tp)
>
> static inline void tcp_snd_cwnd_set(struct tcp_sock *tp, u32 val)
> {
> - WARN_ON_ONCE((int)val <= 0);
> + TCP_SOCK_WARN_ON_ONCE(tp, (int)val <= 0);
> tp->snd_cwnd = val;
> }
>
> diff --git a/include/net/tcp_debug.h b/include/net/tcp_debug.h
> new file mode 100644
> index 000000000000..50e96d87d335
> --- /dev/null
> +++ b/include/net/tcp_debug.h
> @@ -0,0 +1,10 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +#ifndef _LINUX_TCP_DEBUG_H
> +#define _LINUX_TCP_DEBUG_H
> +
> +void tcp_sock_warn(const struct tcp_sock *tp);
> +
> +#define TCP_SOCK_WARN_ON_ONCE(tcp_sock, condition) \
> + DO_ONCE_LITE_IF(condition, tcp_sock_warn, tcp_sock)
> +
> +#endif /* _LINUX_TCP_DEBUG_H */
> diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
> index 54836a6b81d6..5985ba9c4231 100644
> --- a/net/ipv4/tcp.c
> +++ b/net/ipv4/tcp.c
> @@ -4705,6 +4705,36 @@ int tcp_abort(struct sock *sk, int err)
> }
> EXPORT_SYMBOL_GPL(tcp_abort);
>
> +void tcp_sock_warn(const struct tcp_sock *tp)
> +{
> + const struct sock *sk = (const struct sock *)tp;
> + struct inet_sock *inet = inet_sk(sk);
> + struct inet_connection_sock *icsk = inet_csk(sk);
Let's keep the reverse christmas tree order.
$ cat -n Documentation/process/maintainer-netdev.rst | grep xmas -C 30
> +
> + WARN_ON(1);
> +
> + pr_warn("Socket Info: family=%u state=%d ccname=%s cwnd=%u",
> + sk->sk_family, sk->sk_state, icsk->icsk_ca_ops->name,
> + tcp_snd_cwnd(tp));
> +
> + switch (sk->sk_family) {
> + case AF_INET:
> + pr_warn("saddr=%pI4:%u daddr=%pI4:%u", &inet->inet_saddr,
> + ntohs(inet->inet_sport), &inet->inet_daddr,
> + ntohs(inet->inet_dport));
> +
> + break;
> +#if IS_ENABLED(CONFIG_IPV6)
> + case AF_INET6:
> + pr_warn("saddr=[%pI6]:%u daddr=[%pI6]:%u", &sk->sk_v6_rcv_saddr,
> + ntohs(inet->inet_sport), &sk->sk_v6_daddr,
> + ntohs(inet->inet_dport));
> + break;
> +#endif
> + }
> +}
> +EXPORT_SYMBOL_GPL(tcp_sock_warn);
> +
> extern struct tcp_congestion_ops tcp_reno;
>
> static __initdata unsigned long thash_entries;
> --
> 2.30.2
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH v2 net-next] tcp: socket-specific version of WARN_ON_ONCE()
2022-12-08 15:46 [PATCH v2 net-next] tcp: socket-specific version of WARN_ON_ONCE() Breno Leitao
2022-12-09 7:55 ` Kuniyuki Iwashima
@ 2022-12-11 8:44 ` Sven Schnelle
1 sibling, 0 replies; 3+ messages in thread
From: Sven Schnelle @ 2022-12-11 8:44 UTC (permalink / raw)
To: Breno Leitao
Cc: edumazet, davem, kuba, pabeni, kuniyu, netdev, leit, yoshfuji,
dsahern, linux-kernel
Breno Leitao <leitao@debian.org> writes:
> There are cases where we need relevant information about the socket
> during a warning, so, it could help us to find bugs that happens and do
> not have an easy repro.
>
> This patch creates a TCP-socket specific version of WARN_ON_ONCE(), which
> dumps revelant information about the TCP socket when it hits rare
> warnings, which is super useful for debugging purposes.
>
> Hooking this warning tcp_snd_cwnd_set() for now, but, the intent is to
> convert more TCP warnings to this helper later.
>
> Signed-off-by: Breno Leitao <leitao@debian.org>
> ---
> include/net/tcp.h | 3 ++-
> include/net/tcp_debug.h | 10 ++++++++++
> net/ipv4/tcp.c | 30 ++++++++++++++++++++++++++++++
> 3 files changed, 42 insertions(+), 1 deletion(-)
> create mode 100644 include/net/tcp_debug.h
>
> diff --git a/include/net/tcp.h b/include/net/tcp.h
> index 14d45661a84d..e490af8e6fdc 100644
> --- a/include/net/tcp.h
> +++ b/include/net/tcp.h
> @@ -40,6 +40,7 @@
> #include <net/inet_ecn.h>
> #include <net/dst.h>
> #include <net/mptcp.h>
> +#include <net/tcp_debug.h>
>
> #include <linux/seq_file.h>
> #include <linux/memcontrol.h>
> @@ -1229,7 +1230,7 @@ static inline u32 tcp_snd_cwnd(const struct tcp_sock *tp)
>
> static inline void tcp_snd_cwnd_set(struct tcp_sock *tp, u32 val)
> {
> - WARN_ON_ONCE((int)val <= 0);
> + TCP_SOCK_WARN_ON_ONCE(tp, (int)val <= 0);
> tp->snd_cwnd = val;
> }
>
> diff --git a/include/net/tcp_debug.h b/include/net/tcp_debug.h
> new file mode 100644
> index 000000000000..50e96d87d335
> --- /dev/null
> +++ b/include/net/tcp_debug.h
> @@ -0,0 +1,10 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +#ifndef _LINUX_TCP_DEBUG_H
> +#define _LINUX_TCP_DEBUG_H
> +
> +void tcp_sock_warn(const struct tcp_sock *tp);
> +
> +#define TCP_SOCK_WARN_ON_ONCE(tcp_sock, condition) \
> + DO_ONCE_LITE_IF(condition, tcp_sock_warn, tcp_sock)
> +
> +#endif /* _LINUX_TCP_DEBUG_H */
> diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
> index 54836a6b81d6..5985ba9c4231 100644
> --- a/net/ipv4/tcp.c
> +++ b/net/ipv4/tcp.c
> @@ -4705,6 +4705,36 @@ int tcp_abort(struct sock *sk, int err)
> }
> EXPORT_SYMBOL_GPL(tcp_abort);
>
> +void tcp_sock_warn(const struct tcp_sock *tp)
> +{
> + const struct sock *sk = (const struct sock *)tp;
> + struct inet_sock *inet = inet_sk(sk);
> + struct inet_connection_sock *icsk = inet_csk(sk);
> +
> + WARN_ON(1);
Never looked into the details of WARN_ON, but shouldn't that come at the
end of the function? If one has kernel.panic_on_warn=1, the kernel
would already panic in WARN_ON, and the lines below wouldn't be printed?
> +
> + pr_warn("Socket Info: family=%u state=%d ccname=%s cwnd=%u",
> + sk->sk_family, sk->sk_state, icsk->icsk_ca_ops->name,
> + tcp_snd_cwnd(tp));
> +
> + switch (sk->sk_family) {
> + case AF_INET:
> + pr_warn("saddr=%pI4:%u daddr=%pI4:%u", &inet->inet_saddr,
> + ntohs(inet->inet_sport), &inet->inet_daddr,
> + ntohs(inet->inet_dport));
> +
> + break;
> +#if IS_ENABLED(CONFIG_IPV6)
> + case AF_INET6:
> + pr_warn("saddr=[%pI6]:%u daddr=[%pI6]:%u", &sk->sk_v6_rcv_saddr,
> + ntohs(inet->inet_sport), &sk->sk_v6_daddr,
> + ntohs(inet->inet_dport));
> + break;
> +#endif
> + }
> +}
> +EXPORT_SYMBOL_GPL(tcp_sock_warn);
> +
> extern struct tcp_congestion_ops tcp_reno;
>
> static __initdata unsigned long thash_entries;
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2022-12-11 8:45 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2022-12-08 15:46 [PATCH v2 net-next] tcp: socket-specific version of WARN_ON_ONCE() Breno Leitao
2022-12-09 7:55 ` Kuniyuki Iwashima
2022-12-11 8:44 ` Sven Schnelle
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).