Files
linux/tools/testing/selftests/drivers/net/netcons_torture.sh
Breno Leitao 6701896eb9 selftest: netcons: create a torture test
Create a netconsole test that puts a lot of pressure on the netconsole
list manipulation. Do it by creating dynamic targets and deleting
targets while messages are being sent. Also put interface down while the
messages are being sent, as creating parallel targets.

The code launches three background jobs on distinct schedules:

 * Toggle netcons target every 30 iterations
 * create and delete random_target every 50 iterations
 * toggle iface every 70 iterations

This creates multiple concurrency sources that interact with netconsole
states. This is good practice to simulate stress, and exercise netpoll
and netconsole locks.

This test already found an issue as reported in [1]

Link: https://lore.kernel.org/all/20250901-netpoll_memleak-v1-1-34a181977dfc@debian.org/ [1]
Signed-off-by: Breno Leitao <leitao@debian.org>
Reviewed-by: Andre Carvalho <asantostc@gmail.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20251107-netconsole_torture-v10-3-749227b55f63@debian.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-11-10 18:34:44 -08:00

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#!/usr/bin/env bash
# SPDX-License-Identifier: GPL-2.0
# Repeatedly send kernel messages, toggles netconsole targets on and off,
# creates and deletes targets in parallel, and toggles the source interface to
# simulate stress conditions.
#
# This test aims to verify the robustness of netconsole under dynamic
# configurations and concurrent operations.
#
# The major goal is to run this test with LOCKDEP, Kmemleak and KASAN to make
# sure no issues is reported.
#
# Author: Breno Leitao <leitao@debian.org>
set -euo pipefail
SCRIPTDIR=$(dirname "$(readlink -e "${BASH_SOURCE[0]}")")
source "${SCRIPTDIR}"/lib/sh/lib_netcons.sh
# Number of times the main loop run
ITERATIONS=${1:-150}
# Only test extended format
FORMAT="extended"
# And ipv6 only
IP_VERSION="ipv6"
# Create, enable and delete some targets.
create_and_delete_random_target() {
COUNT=2
RND_PREFIX=$(mktemp -u netcons_rnd_XXXX_)
if [ -d "${NETCONS_CONFIGFS}/${RND_PREFIX}${COUNT}" ] || \
[ -d "${NETCONS_CONFIGFS}/${RND_PREFIX}0" ]; then
echo "Function didn't finish yet, skipping it." >&2
return
fi
# enable COUNT targets
for i in $(seq ${COUNT})
do
RND_TARGET="${RND_PREFIX}"${i}
RND_TARGET_PATH="${NETCONS_CONFIGFS}"/"${RND_TARGET}"
# Basic population so the target can come up
_create_dynamic_target "${FORMAT}" "${RND_TARGET_PATH}"
done
echo "netconsole selftest: ${COUNT} additional targets were created" > /dev/kmsg
# disable them all
for i in $(seq ${COUNT})
do
RND_TARGET="${RND_PREFIX}"${i}
RND_TARGET_PATH="${NETCONS_CONFIGFS}"/"${RND_TARGET}"
if [[ $(cat "${RND_TARGET_PATH}/enabled") -eq 1 ]]
then
echo 0 > "${RND_TARGET_PATH}"/enabled
fi
rmdir "${RND_TARGET_PATH}"
done
}
# Disable and enable the target mid-air, while messages
# are being transmitted.
toggle_netcons_target() {
for i in $(seq 2)
do
if [ ! -d "${NETCONS_PATH}" ]
then
break
fi
echo 0 > "${NETCONS_PATH}"/enabled 2> /dev/null || true
# Try to enable a bit harder, given it might fail to enable
# Write to `enabled` might fail depending on the lock, which is
# highly contentious here
for _ in $(seq 5)
do
echo 1 > "${NETCONS_PATH}"/enabled 2> /dev/null || true
done
done
}
toggle_iface(){
ip link set "${SRCIF}" down
ip link set "${SRCIF}" up
}
# Start here
modprobe netdevsim 2> /dev/null || true
modprobe netconsole 2> /dev/null || true
# Check for basic system dependency and exit if not found
check_for_dependencies
# Set current loglevel to KERN_INFO(6), and default to KERN_NOTICE(5)
echo "6 5" > /proc/sys/kernel/printk
# Remove the namespace, interfaces and netconsole target on exit
trap cleanup EXIT
# Create one namespace and two interfaces
set_network "${IP_VERSION}"
# Create a dynamic target for netconsole
create_dynamic_target "${FORMAT}"
for i in $(seq "$ITERATIONS")
do
for _ in $(seq 10)
do
echo "${MSG}: ${TARGET} ${i}" > /dev/kmsg
done
wait
if (( i % 30 == 0 )); then
toggle_netcons_target &
fi
if (( i % 50 == 0 )); then
# create some targets, enable them, send msg and disable
# all in a parallel thread
create_and_delete_random_target &
fi
if (( i % 70 == 0 )); then
toggle_iface &
fi
done
wait
exit "${EXIT_STATUS}"