From eccd0a80dc7f4be65430236db475546b0ab9ec37 Mon Sep 17 00:00:00 2001 From: Vladimir Oltean Date: Sun, 24 Oct 2021 20:17:57 +0300 Subject: selftests: net: dsa: add a stress test for unlocked FDB operations This test is a bit strange in that it is perhaps more manual than others: it does not transmit a clear OK/FAIL verdict, because user space does not have synchronous feedback from the kernel. If a hardware access fails, it is in deferred context. Nonetheless, on sja1105 I have used it successfully to find and solve a concurrency issue, so it can be used as a starting point for other driver maintainers too. Signed-off-by: Vladimir Oltean Reviewed-by: Florian Fainelli Signed-off-by: David S. Miller --- .../drivers/net/dsa/test_bridge_fdb_stress.sh | 47 ++++++++++++++++++++++ 1 file changed, 47 insertions(+) create mode 100755 tools/testing/selftests/drivers/net/dsa/test_bridge_fdb_stress.sh (limited to 'tools/testing/selftests') diff --git a/tools/testing/selftests/drivers/net/dsa/test_bridge_fdb_stress.sh b/tools/testing/selftests/drivers/net/dsa/test_bridge_fdb_stress.sh new file mode 100755 index 000000000000..dca8be6092b9 --- /dev/null +++ b/tools/testing/selftests/drivers/net/dsa/test_bridge_fdb_stress.sh @@ -0,0 +1,47 @@ +#!/bin/bash +# SPDX-License-Identifier: GPL-2.0 + +# Bridge FDB entries can be offloaded to DSA switches without holding the +# rtnl_mutex. Traditionally this mutex has conferred drivers implicit +# serialization, which means their code paths are not well tested in the +# presence of concurrency. +# This test creates a background task that stresses the FDB by adding and +# deleting an entry many times in a row without the rtnl_mutex held. +# It then tests the driver resistance to concurrency by calling .ndo_fdb_dump +# (with rtnl_mutex held) from a foreground task. +# Since either the FDB dump or the additions/removals can fail, but the +# additions and removals are performed in deferred as opposed to process +# context, we cannot simply check for user space error codes. + +WAIT_TIME=1 +NUM_NETIFS=1 +REQUIRE_JQ="no" +REQUIRE_MZ="no" +NETIF_CREATE="no" +lib_dir=$(dirname $0)/../../../net/forwarding +source $lib_dir/lib.sh + +cleanup() { + echo "Cleaning up" + kill $pid && wait $pid &> /dev/null + ip link del br0 + echo "Please check kernel log for errors" +} +trap 'cleanup' EXIT + +eth=${NETIFS[p1]} + +ip link del br0 2&>1 >/dev/null || : +ip link add br0 type bridge && ip link set $eth master br0 + +(while :; do + bridge fdb add 00:01:02:03:04:05 dev $eth master static + bridge fdb del 00:01:02:03:04:05 dev $eth master static +done) & +pid=$! + +for i in $(seq 1 50); do + bridge fdb show > /dev/null + sleep 3 + echo "$((${i} * 2))% complete..." +done -- cgit v1.2.3