[PATCH] selftests: add new kallsyms selftests
From: Luis Chamberlain
Date: Fri Dec 22 2023 - 14:22:08 EST
Signed-off-by: Luis Chamberlain <mcgrof@xxxxxxxxxx>
---
lib/Kconfig.debug | 95 +++++++++++++
lib/Makefile | 1 +
lib/tests/Makefile | 1 +
lib/tests/module/.gitignore | 4 +
lib/tests/module/Makefile | 15 ++
lib/tests/module/gen_test_kallsyms.sh | 128 ++++++++++++++++++
tools/testing/selftests/module/Makefile | 12 ++
tools/testing/selftests/module/config | 7 +
tools/testing/selftests/module/find_symbol.sh | 65 +++++++++
9 files changed, 328 insertions(+)
create mode 100644 lib/tests/Makefile
create mode 100644 lib/tests/module/.gitignore
create mode 100644 lib/tests/module/Makefile
create mode 100755 lib/tests/module/gen_test_kallsyms.sh
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
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 97ce28f4d154..4f5fbaceaf88 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -2835,6 +2835,101 @@ config TEST_KMOD
If unsure, say N.
+config TEST_RUNTIME
+ bool
+
+config TEST_RUNTIME_MODULE
+ bool
+
+config TEST_KALLSYMS
+ tristate "module kallsyms find_symbol() test"
+ depends on m
+ select TEST_RUNTIME
+ select TEST_RUNTIME_MODULE
+ select TEST_KALLSYMS_A
+ select TEST_KALLSYMS_B
+ select TEST_KALLSYMS_C
+ select TEST_KALLSYMS_D
+ help
+ This allows us to stress test find_symbol() through the kallsyms
+ used to place symbols on the kernel ELF kallsyms and modules kallsyms
+ where we place kernel symbols such as exported symbols.
+
+ We have four 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
+
+ We stress test find_symbol() through two means:
+
+ 1) Upon load of B it will trigger simplify_symbols() to look for the
+ one symbol it uses from the module A with tons of symbols. This is an
+ indirect way for us to have B call resolve_symbol_wait() upon module
+ load. This will eventually call find_symbol() which will eventually
+ try to find the symbols used with find_exported_symbol_in_section().
+ find_exported_symbol_in_section() uses bsearch() so a binary search
+ for each symbol. Binary search will at worst be O(log(n)) so the
+ larger TEST_MODULE_KALLSYSMS the worse the search.
+
+ 2) The selftests should load C first, before B. Upon B's load towards
+ the end right before we call module B's init routine we get
+ complete_formation() called on the module. That will first check
+ for duplicate symbols with the call to verify_exported_symbols().
+ That is when we'll force iteration on module C's insane symbol list.
+ Since it has 10 * KALLSYMS_NUMSYMS it means we can first test
+ just loading B without C. The amount of time it takes to load C Vs
+ B can give us an idea of the impact growth of the symbol space and
+ give us projection. Module A only uses one symbol from B so to allow
+ this scaling in module C to be proportional, if it used more symbols
+ then the first test would be doing more and increasing just the
+ search space would be slightly different. The last module, module D
+ will just increase the search space by twice the number of symbols in
+ C so to allow for full projects.
+
+ tools/testing/selftests/module/find_symbol.sh
+
+ If unsure, say N.
+
+if TEST_KALLSYMS
+
+config TEST_KALLSYMS_A
+ tristate
+ depends on m
+
+config TEST_KALLSYMS_B
+ tristate
+ depends on m
+
+config TEST_KALLSYMS_C
+ tristate
+ depends on m
+
+config TEST_KALLSYMS_D
+ tristate
+ depends on m
+
+config TEST_KALLSYMS_NUMSYMS
+ int "test kallsyms number of symbols"
+ default 10000
+ help
+ The number of symbols to create on TEST_KALLSYMS_A, only one of which
+ module TEST_KALLSYMS_B will use. This also will be used
+ for how many symbols TEST_KALLSYMS_C will have, scaled up by
+ TEST_KALLSYMS_SCALE_FACTOR.
+
+config TEST_KALLSYMS_SCALE_FACTOR
+ int "test kallsyms scale factor"
+ default 4
+ help
+ How many more unusued symbols will TEST_KALLSYSMS_C have than
+ TEST_KALLSYMS_A. If 4, then module C will have 4 * syms
+ than module A. Then TEST_KALLSYMS_D will have double the amount
+ of symbols than C so to allow projections.
+
+endif # TEST_KALLSYMS
+
config TEST_DEBUG_VIRTUAL
tristate "Test CONFIG_DEBUG_VIRTUAL feature"
depends on DEBUG_VIRTUAL
diff --git a/lib/Makefile b/lib/Makefile
index 6b09731d8e61..48e69a61cd85 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -95,6 +95,7 @@ obj-$(CONFIG_TEST_XARRAY) += test_xarray.o
obj-$(CONFIG_TEST_MAPLE_TREE) += test_maple_tree.o
obj-$(CONFIG_TEST_PARMAN) += test_parman.o
obj-$(CONFIG_TEST_KMOD) += test_kmod.o
+obj-$(CONFIG_TEST_RUNTIME) += tests/
obj-$(CONFIG_TEST_DEBUG_VIRTUAL) += test_debug_virtual.o
obj-$(CONFIG_TEST_MEMCAT_P) += test_memcat_p.o
obj-$(CONFIG_TEST_OBJAGG) += test_objagg.o
diff --git a/lib/tests/Makefile b/lib/tests/Makefile
new file mode 100644
index 000000000000..8e4f42cb9c54
--- /dev/null
+++ b/lib/tests/Makefile
@@ -0,0 +1 @@
+obj-$(CONFIG_TEST_RUNTIME_MODULE) += module/
diff --git a/lib/tests/module/.gitignore b/lib/tests/module/.gitignore
new file mode 100644
index 000000000000..8be7891b250f
--- /dev/null
+++ b/lib/tests/module/.gitignore
@@ -0,0 +1,4 @@
+test_kallsyms_a.c
+test_kallsyms_b.c
+test_kallsyms_c.c
+test_kallsyms_d.c
diff --git a/lib/tests/module/Makefile b/lib/tests/module/Makefile
new file mode 100644
index 000000000000..af5c27b996cb
--- /dev/null
+++ b/lib/tests/module/Makefile
@@ -0,0 +1,15 @@
+obj-$(CONFIG_TEST_KALLSYMS_A) += test_kallsyms_a.o
+obj-$(CONFIG_TEST_KALLSYMS_B) += test_kallsyms_b.o
+obj-$(CONFIG_TEST_KALLSYMS_C) += test_kallsyms_c.o
+obj-$(CONFIG_TEST_KALLSYMS_D) += test_kallsyms_d.o
+
+$(obj)/%.c: FORCE
+ @$(kecho) " GEN $@"
+ $(Q)$(srctree)/lib/tests/module/gen_test_kallsyms.sh $@\
+ $(CONFIG_TEST_KALLSYMS_NUMSYMS) \
+ $(CONFIG_TEST_KALLSYMS_SCALE_FACTOR)
+
+clean-files += test_kallsyms_a.c
+clean-files += test_kallsyms_b.c
+clean-files += test_kallsyms_c.c
+clean-files += test_kallsyms_d.c
diff --git a/lib/tests/module/gen_test_kallsyms.sh b/lib/tests/module/gen_test_kallsyms.sh
new file mode 100755
index 000000000000..e85f10dc11bd
--- /dev/null
+++ b/lib/tests/module/gen_test_kallsyms.sh
@@ -0,0 +1,128 @@
+#!/bin/bash
+
+TARGET=$(basename $1)
+DIR=lib/tests/module
+TARGET="$DIR/$TARGET"
+NUM_SYMS=$2
+SCALE_FACTOR=$3
+TEST_TYPE=$(echo $TARGET | sed -e 's|lib/tests/module/test_kallsyms_||g')
+TEST_TYPE=$(echo $TEST_TYPE | sed -e 's|.c||g')
+
+gen_template_module_header()
+{
+ cat <<____END_MODULE
+// SPDX-License-Identifier: GPL-2.0-or-later OR copyleft-next-0.3.1
+/*
+ * Copyright (C) 2023 Luis Chamberlain <mcgrof@xxxxxxxxxx>
+ *
+ * Automatically generated code for testing, do not edit manually.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/printk.h>
+
+____END_MODULE
+}
+
+gen_num_syms()
+{
+ PREFIX=$1
+ NUM=$2
+ for i in $(seq 1 $NUM); do
+ printf "int auto_test_%s_%010d = 0xff;\n" $PREFIX $i
+ printf "EXPORT_SYMBOL_GPL(auto_test_%s_%010d);\n" $PREFIX $i
+ done
+ echo
+}
+
+gen_template_module_data_a()
+{
+ gen_num_syms a $1
+ cat <<____END_MODULE
+static int auto_runtime_test(void)
+{
+ return 0;
+}
+
+____END_MODULE
+}
+
+gen_template_module_data_b()
+{
+ printf "\nextern int auto_test_a_%010d;\n\n" 28
+ echo "static int auto_runtime_test(void)"
+ echo "{"
+ printf "\nreturn auto_test_a_%010d;\n" 28
+ echo "}"
+}
+
+gen_template_module_data_c()
+{
+ gen_num_syms c $1
+ cat <<____END_MODULE
+static int auto_runtime_test(void)
+{
+ return 0;
+}
+
+____END_MODULE
+}
+
+gen_template_module_data_d()
+{
+ gen_num_syms d $1
+ cat <<____END_MODULE
+static int auto_runtime_test(void)
+{
+ return 0;
+}
+
+____END_MODULE
+}
+
+gen_template_module_exit()
+{
+ cat <<____END_MODULE
+static int __init auto_test_module_init(void)
+{
+ return auto_runtime_test();
+}
+module_init(auto_test_module_init);
+
+static void __exit auto_test_module_exit(void)
+{
+}
+module_exit(auto_test_module_exit);
+
+MODULE_AUTHOR("Luis Chamberlain <mcgrof@xxxxxxxxxx>");
+MODULE_LICENSE("GPL");
+____END_MODULE
+}
+
+case $TEST_TYPE in
+ a)
+ gen_template_module_header > $TARGET
+ gen_template_module_data_a $NUM_SYMS >> $TARGET
+ gen_template_module_exit >> $TARGET
+ ;;
+ b)
+ gen_template_module_header > $TARGET
+ gen_template_module_data_b >> $TARGET
+ gen_template_module_exit >> $TARGET
+ ;;
+ c)
+ gen_template_module_header > $TARGET
+ gen_template_module_data_c $((NUM_SYMS * SCALE_FACTOR)) >> $TARGET
+ gen_template_module_exit >> $TARGET
+ ;;
+ d)
+ gen_template_module_header > $TARGET
+ gen_template_module_data_d $((NUM_SYMS * SCALE_FACTOR * 2)) >> $TARGET
+ gen_template_module_exit >> $TARGET
+ ;;
+ *)
+ ;;
+esac
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..259f4fd6b5e2
--- /dev/null
+++ b/tools/testing/selftests/module/config
@@ -0,0 +1,7 @@
+CONFIG_TEST_KMOD=m
+CONFIG_TEST_LKM=m
+CONFIG_XFS_FS=m
+
+# For the module parameter force_init_test is used
+CONFIG_TUN=m
+CONFIG_BTRFS_FS=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..c206b42525f1
--- /dev/null
+++ b/tools/testing/selftests/module/find_symbol.sh
@@ -0,0 +1,65 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0-or-later OR copyleft-next-0.3.1
+# Copyright (C) 2023 Luis Chamberlain <mcgrof@xxxxxxxxxx>
+#
+# 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
+}
+
+remove_all()
+{
+ $MODPROBE -r test_kallsyms_b
+ for i in a b c d; do
+ $MODPROBE -r test_kallsyms_$i
+ done
+}
+test_reqs
+
+MODPROBE=$(</proc/sys/kernel/modprobe)
+STATS="-e duration_time"
+STATS="$STATS -e user_time"
+STATS="$STATS -e system_time"
+STATS="$STATS -e page-faults"
+
+remove_all
+perf stat $STATS $MODPROBE test_kallsyms_b
+remove_all
+
+# Now pollute the namespace
+$MODPROBE test_kallsyms_c
+perf stat $STATS $MODPROBE test_kallsyms_b
+
+# Now pollute the namespace with twice the number of symbols than the last time
+remove_all
+$MODPROBE test_kallsyms_c
+$MODPROBE test_kallsyms_d
+perf stat $STATS $MODPROBE test_kallsyms_b
+
+exit 0
--
2.42.0