Commit eccd0a80 authored by Vladimir Oltean's avatar Vladimir Oltean Committed by David S. Miller
Browse files

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: default avatarVladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: default avatarFlorian Fainelli <f.fainelli@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent d70b51f2

MAINTAINERS

+1 −0
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@@ -13056,6 +13056,7 @@ F: include/linux/dsa/ 
F:	include/linux/platform_data/dsa.h

F:	include/net/dsa.h

F:	net/dsa/

F:	tools/testing/selftests/drivers/net/dsa/









NETWORKING [GENERAL]









M:	"David S. Miller" <davem@davemloft.net>
































tools/testing/selftests/drivers/net/dsa/test_bridge_fdb_stress.sh
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#!/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