[PATCH net-next 2/4] net: add CONFIG_DEBUG_NET

[Eric Dumazet <eric.dumazet@gmail.com>]

From: Eric Dumazet <edumazet@google.com>

This config option enables network debugging checks.

This patch adds DEBUG_NET_WARN_ON_ONCE(cond)
Note that this is not a replacement for WARN_ON_ONCE(cond)
as (cond) is not evaluated if CONFIG_DEBUG_NET is not set.

Signed-off-by: Eric Dumazet <edumazet@google.com>
---
 include/net/net_debug.h | 6 ++++++
 net/Kconfig.debug       | 7 +++++++
 2 files changed, 13 insertions(+)

diff --git a/include/net/net_debug.h b/include/net/net_debug.h
index d8769ee7bced92decf126fe6c521db75e458565c..f972ed3766a157f3f4de958fb6d4789dffc2923c 100644
--- a/include/net/net_debug.h
+++ b/include/net/net_debug.h
@@ -156,4 +156,10 @@ do {								\
 #endif
 
 
+#if defined(CONFIG_DEBUG_NET)
+#define DEBUG_NET_WARN_ON_ONCE(cond) (void)WARN_ON_ONCE(cond)
+#else
+#define DEBUG_NET_WARN_ON_ONCE(cond) BUILD_BUG_ON_INVALID(cond)
+#endif
+
 #endif	/* _LINUX_NET_DEBUG_H */
diff --git a/net/Kconfig.debug b/net/Kconfig.debug
index 2f50611df858911cf5190a361e4e9316e543ed3a..a5781cf63b16b32e5360df1ca26a753b6505d81f 100644
--- a/net/Kconfig.debug
+++ b/net/Kconfig.debug
@@ -17,3 +17,10 @@ config NET_NS_REFCNT_TRACKER
 	help
 	  Enable debugging feature to track netns references.
 	  This adds memory and cpu costs.
+
+config DEBUG_NET
+	bool "Add generic networking debug"
+	depends on DEBUG_KERNEL
+	help
+	  Enable extra sanity checks in networking.
+	  This is mostly used by fuzzers, but is safe to select.
-- 
2.36.0.512.ge40c2bad7a-goog