diff mbox series

[net-next] tcp: socket-specific version of WARN_ON_ONCE()

Message ID 20220729171554.3992869-1-leitao@debian.org (mailing list archive)
State Deferred
Delegated to: Netdev Maintainers
Headers show
Series [net-next] tcp: socket-specific version of WARN_ON_ONCE() | expand

Checks

Context Check Description
netdev/tree_selection success Clearly marked for net-next, async
netdev/fixes_present success Fixes tag not required for -next series
netdev/subject_prefix success Link
netdev/cover_letter success Single patches do not need cover letters
netdev/patch_count success Link
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 1007 this patch: 1007
netdev/cc_maintainers warning 3 maintainers not CCed: dsahern@kernel.org pabeni@redhat.com yoshfuji@linux-ipv6.org
netdev/build_clang success Errors and warnings before: 125 this patch: 125
netdev/module_param success Was 0 now: 0
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 1014 this patch: 1014
netdev/checkpatch warning WARNING: added, moved or deleted file(s), does MAINTAINERS need updating? WARNING: line length of 84 exceeds 80 columns
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Breno Leitao July 29, 2022, 5:15 p.m. UTC 
There are cases where we need information about the socket during a
warning, so, it could help us to find bugs that happens that do not have
a easily repro.

BPF congestion control algorithms can change socket state in unexpected
ways, leading to WARNings. Additional information about the socket state
is useful to identify the culprit.

This diff creates a TCP socket-specific version of WARN_ON_ONCE(), and
attaches it to tcp_snd_cwnd_set().

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 mbox series

Patch

diff --git a/include/net/tcp.h b/include/net/tcp.h
index 071735e10872..eca7e58a3117 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>
@@ -1216,7 +1217,7 @@  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 2faaaaf540ac..7abd1634e876 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -4556,6 +4556,36 @@  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);
+
+	if (!tp)
+		return;
+
+	pr_warn("Socket Info: family=%u state=%d sport=%u dport=%u ccname=%s cwnd=%u",
+		sk->sk_family, sk->sk_state, ntohs(inet->inet_sport),
+		ntohs(inet->inet_dport), icsk->icsk_ca_ops->name, tcp_snd_cwnd(tp));
+
+	switch (sk->sk_family) {
+	case AF_INET:
+		pr_warn("saddr=%pI4 daddr=%pI4", &inet->inet_saddr,
+			&inet->inet_daddr);
+		break;
+#if IS_ENABLED(CONFIG_IPV6)
+	case AF_INET6:
+		pr_warn("saddr=%pI6 daddr=%pI6", &sk->sk_v6_rcv_saddr,
+			&sk->sk_v6_daddr);
+		break;
+#endif
+	}
+}
+EXPORT_SYMBOL_GPL(tcp_sock_warn);
+
 extern struct tcp_congestion_ops tcp_reno;
 
 static __initdata unsigned long thash_entries;