linux-kernel - [PATCH net-next v2 4/4] netconsole: Increase MAX_USERDATA

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Message-Id: <20251113-netconsole_dynamic_extradata-v2-4-18cf7fed1026@meta.com>
Date: Thu, 13 Nov 2025 08:42:21 -0800
From: Gustavo Luiz Duarte <gustavold@...il.com>
To: Breno Leitao <leitao@...ian.org>, Andre Carvalho <asantostc@...il.com>, 
 Simon Horman <horms@...nel.org>, Andrew Lunn <andrew+netdev@...n.ch>, 
 "David S. Miller" <davem@...emloft.net>, Eric Dumazet <edumazet@...gle.com>, 
 Jakub Kicinski <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>, 
 Shuah Khan <shuah@...nel.org>
Cc: netdev@...r.kernel.org, linux-kernel@...r.kernel.org, 
 linux-kselftest@...r.kernel.org, Gustavo Luiz Duarte <gustavold@...il.com>
Subject: [PATCH net-next v2 4/4] netconsole: Increase MAX_USERDATA_ITEMS

Increase MAX_USERDATA_ITEMS from 16 to 256 entries now that the userdata
buffer is allocated dynamically.

The previous limit of 16 was necessary because the buffer was statically
allocated for all targets. With dynamic allocation, we can support more
entries without wasting memory on targets that don't use userdata.

This allows users to attach more metadata to their netconsole messages,
which is useful for complex debugging and logging scenarios.

Also update the testcase accordingly.

Signed-off-by: Gustavo Luiz Duarte <gustavold@...il.com>
---
 drivers/net/netconsole.c                                | 2 +-
 tools/testing/selftests/drivers/net/netcons_overflow.sh | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c
index 12fbc303a8240..36ce19936fa39 100644
--- a/drivers/net/netconsole.c
+++ b/drivers/net/netconsole.c
@@ -50,7 +50,7 @@ MODULE_LICENSE("GPL");
 /* The number 3 comes from userdata entry format characters (' ', '=', '\n') */
 #define MAX_EXTRADATA_NAME_LEN		(MAX_EXTRADATA_ENTRY_LEN - \
 					MAX_EXTRADATA_VALUE_LEN - 3)
-#define MAX_USERDATA_ITEMS		16
+#define MAX_USERDATA_ITEMS		256
 #define MAX_PRINT_CHUNK			1000

 static char config[MAX_PARAM_LENGTH];
diff --git a/tools/testing/selftests/drivers/net/netcons_overflow.sh b/tools/testing/selftests/drivers/net/netcons_overflow.sh
index 29bad56448a24..06089643b7716 100755
--- a/tools/testing/selftests/drivers/net/netcons_overflow.sh
+++ b/tools/testing/selftests/drivers/net/netcons_overflow.sh
@@ -15,7 +15,7 @@ SCRIPTDIR=$(dirname "$(readlink -e "${BASH_SOURCE[0]}")")

 source "${SCRIPTDIR}"/lib/sh/lib_netcons.sh
 # This is coming from netconsole code. Check for it in drivers/net/netconsole.c
-MAX_USERDATA_ITEMS=16
+MAX_USERDATA_ITEMS=256

 # Function to create userdata entries
 function create_userdata_max_entries() {

-- 
2.47.3