From 84b4a51fce4ccc6605113ed8af41a3d91609a756 Mon Sep 17 00:00:00 2001 From: Luis Chamberlain Date: Mon, 21 Oct 2024 12:11:44 -0700 Subject: selftests: add new kallsyms selftests We lack find_symbol() selftests, so add one. This let's us stress test improvements easily on find_symbol() or optimizations. It also inherently allows us to test the limits of kallsyms on Linux today. We test a pathalogical use case for kallsyms by introducing modules which are automatically written for us with a larger number of symbols. We have 4 kallsyms test modules: A: has KALLSYSMS_NUMSYMS exported symbols B: uses one of A's symbols C: adds KALLSYMS_SCALE_FACTOR * KALLSYSMS_NUMSYMS exported D: adds 2 * the symbols than C By using anything much larger than KALLSYSMS_NUMSYMS as 10,000 and KALLSYMS_SCALE_FACTOR of 8 we segfault today. So we're capped at around 160000 symbols somehow today. We can inpsect that issue at our leasure later, but for now the real value to this test is that this will easily allow us to test improvements on find_symbol(). We want to enable this test on allyesmodconfig builds so we can't use this combination, so instead just use a safe value for now and be informative on the Kconfig symbol documentation about where our thresholds are for testers. We default then to KALLSYSMS_NUMSYMS of just 100 and KALLSYMS_SCALE_FACTOR of 8. On x86_64 we can use perf, for other architectures we just use 'time' and allow for customizations. For example a future enhancements could be done for parisc to check for unaligned accesses which triggers a special special exception handler assembler code inside the kernel. The negative impact on performance is so large on parisc that it keeps track of its accesses on /proc/cpuinfo as UAH: IRQ: CPU0 CPU1 3: 1332 0 SuperIO ttyS0 7: 1270013 0 SuperIO pata_ns87415 64: 320023012 320021431 CPU timer 65: 17080507 20624423 CPU IPI UAH: 10948640 58104 Unaligned access handler traps While at it, this tidies up lib/ test modules to allow us to have a new directory for them. The amount of test modules under lib/ is insane. This should also hopefully showcase how to start doing basic self module writing code, which may be more useful for more complex cases later in the future. Signed-off-by: Luis Chamberlain --- tools/testing/selftests/module/Makefile | 12 ++++ tools/testing/selftests/module/config | 3 + tools/testing/selftests/module/find_symbol.sh | 81 +++++++++++++++++++++++++++ 3 files changed, 96 insertions(+) create mode 100644 tools/testing/selftests/module/Makefile create mode 100644 tools/testing/selftests/module/config create mode 100755 tools/testing/selftests/module/find_symbol.sh (limited to 'tools/testing/selftests/module') diff --git a/tools/testing/selftests/module/Makefile b/tools/testing/selftests/module/Makefile new file mode 100644 index 000000000000..6132d7ddb08b --- /dev/null +++ b/tools/testing/selftests/module/Makefile @@ -0,0 +1,12 @@ +# SPDX-License-Identifier: GPL-2.0-only +# Makefile for module loading selftests + +# No binaries, but make sure arg-less "make" doesn't trigger "run_tests" +all: + +TEST_PROGS := find_symbol.sh + +include ../lib.mk + +# Nothing to clean up. +clean: diff --git a/tools/testing/selftests/module/config b/tools/testing/selftests/module/config new file mode 100644 index 000000000000..b0c206b1ad47 --- /dev/null +++ b/tools/testing/selftests/module/config @@ -0,0 +1,3 @@ +CONFIG_TEST_RUNTIME=y +CONFIG_TEST_RUNTIME_MODULE=y +CONFIG_TEST_KALLSYMS=m diff --git a/tools/testing/selftests/module/find_symbol.sh b/tools/testing/selftests/module/find_symbol.sh new file mode 100755 index 000000000000..140364d3c49f --- /dev/null +++ b/tools/testing/selftests/module/find_symbol.sh @@ -0,0 +1,81 @@ +#!/bin/bash +# SPDX-License-Identifier: GPL-2.0-or-later OR copyleft-next-0.3.1 +# Copyright (C) 2023 Luis Chamberlain +# +# This is a stress test script for kallsyms through find_symbol() + +set -e + +# Kselftest framework requirement - SKIP code is 4. +ksft_skip=4 + +test_reqs() +{ + if ! which modprobe 2> /dev/null > /dev/null; then + echo "$0: You need modprobe installed" >&2 + exit $ksft_skip + fi + + if ! which kmod 2> /dev/null > /dev/null; then + echo "$0: You need kmod installed" >&2 + exit $ksft_skip + fi + + if ! which perf 2> /dev/null > /dev/null; then + echo "$0: You need perf installed" >&2 + exit $ksft_skip + fi + + uid=$(id -u) + if [ $uid -ne 0 ]; then + echo $msg must be run as root >&2 + exit $ksft_skip + fi +} + +load_mod() +{ + local STATS="-e duration_time" + STATS="$STATS -e user_time" + STATS="$STATS -e system_time" + STATS="$STATS -e page-faults" + local MOD=$1 + + local ARCH="$(uname -m)" + case "${ARCH}" in + x86_64) + perf stat $STATS $MODPROBE test_kallsyms_b + ;; + *) + time $MODPROBE test_kallsyms_b + exit 1 + ;; + esac +} + +remove_all() +{ + $MODPROBE -r test_kallsyms_b + for i in a b c d; do + $MODPROBE -r test_kallsyms_$i + done +} +test_reqs + +MODPROBE=$( Date: Thu, 28 Nov 2024 15:04:52 +0100 Subject: selftests: find_symbol: Actually use load_mod() parameter The parameter passed to load_mod() is stored in $MOD, but never used. Obviously it was intended to be used instead of the hardcoded "test_kallsyms_b" module name. Fixes: 84b4a51fce4ccc66 ("selftests: add new kallsyms selftests") Signed-off-by: Geert Uytterhoeven Signed-off-by: Luis Chamberlain --- tools/testing/selftests/module/find_symbol.sh | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'tools/testing/selftests/module') diff --git a/tools/testing/selftests/module/find_symbol.sh b/tools/testing/selftests/module/find_symbol.sh index 140364d3c49f..2c56805c9b6e 100755 --- a/tools/testing/selftests/module/find_symbol.sh +++ b/tools/testing/selftests/module/find_symbol.sh @@ -44,10 +44,10 @@ load_mod() local ARCH="$(uname -m)" case "${ARCH}" in x86_64) - perf stat $STATS $MODPROBE test_kallsyms_b + perf stat $STATS $MODPROBE $MOD ;; *) - time $MODPROBE test_kallsyms_b + time $MODPROBE $MOD exit 1 ;; esac -- cgit v1.2.3