Add a test for the API which allows the user to specify functions which are then searched for on any tasks's stack during a transition process.
Signed-off-by: Miroslav Benes mbenes@suse.cz --- lib/Kconfig.debug | 1 + lib/livepatch/Makefile | 4 +- lib/livepatch/test_klp_funcstack_demo.c | 61 +++++++++++++ lib/livepatch/test_klp_funcstack_mod.c | 72 +++++++++++++++ tools/testing/selftests/livepatch/Makefile | 3 +- .../selftests/livepatch/test-func-stack.sh | 88 +++++++++++++++++++ 6 files changed, 227 insertions(+), 2 deletions(-) create mode 100644 lib/livepatch/test_klp_funcstack_demo.c create mode 100644 lib/livepatch/test_klp_funcstack_mod.c create mode 100755 tools/testing/selftests/livepatch/test-func-stack.sh
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 9ef7ce18b4f5..aa4c97098f41 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -2529,6 +2529,7 @@ config TEST_LIVEPATCH default n depends on DYNAMIC_DEBUG depends on LIVEPATCH + depends on DEBUG_FS depends on m help Test kernel livepatching features for correctness. The tests will diff --git a/lib/livepatch/Makefile b/lib/livepatch/Makefile index dcc912b3478f..584e3b8b5415 100644 --- a/lib/livepatch/Makefile +++ b/lib/livepatch/Makefile @@ -11,4 +11,6 @@ obj-$(CONFIG_TEST_LIVEPATCH) += test_klp_atomic_replace.o \ test_klp_shadow_vars.o \ test_klp_state.o \ test_klp_state2.o \ - test_klp_state3.o + test_klp_state3.o \ + test_klp_funcstack_mod.o \ + test_klp_funcstack_demo.o diff --git a/lib/livepatch/test_klp_funcstack_demo.c b/lib/livepatch/test_klp_funcstack_demo.c new file mode 100644 index 000000000000..902798077f05 --- /dev/null +++ b/lib/livepatch/test_klp_funcstack_demo.c @@ -0,0 +1,61 @@ +// SPDX-License-Identifier: GPL-2.0 +// Copyright (C) 2021 Miroslav Benes mbenes@suse.cz + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include <linux/module.h> +#include <linux/kernel.h> +#include <linux/livepatch.h> + +static int funcstack; +module_param(funcstack, int, 0644); +MODULE_PARM_DESC(funcstack, "func_stack (default=0)"); + +static noinline void livepatch_child2_function(void) +{ + pr_info("%s\n", __func__); +} + +static struct klp_func funcs[] = { + { + .old_name = "child2_function", + .new_func = livepatch_child2_function, + }, {} +}; + +static struct klp_func funcs_stack[] = { + { + .old_name = "parent_function", + }, {} +}; + +static struct klp_object objs[] = { + { + .name = "test_klp_funcstack_mod", + .funcs = funcs, + }, {} +}; + +static struct klp_patch patch = { + .mod = THIS_MODULE, + .objs = objs, +}; + +static int test_klp_funcstack_demo_init(void) +{ + if (funcstack) + objs[0].funcs_stack = funcs_stack; + + return klp_enable_patch(&patch); +} + +static void test_klp_funcstack_demo_exit(void) +{ +} + +module_init(test_klp_funcstack_demo_init); +module_exit(test_klp_funcstack_demo_exit); +MODULE_LICENSE("GPL"); +MODULE_INFO(livepatch, "Y"); +MODULE_AUTHOR("Miroslav Benes mbenes@suse.cz"); +MODULE_DESCRIPTION("Livepatch test: func_stack demo"); diff --git a/lib/livepatch/test_klp_funcstack_mod.c b/lib/livepatch/test_klp_funcstack_mod.c new file mode 100644 index 000000000000..127c6093d890 --- /dev/null +++ b/lib/livepatch/test_klp_funcstack_mod.c @@ -0,0 +1,72 @@ +// SPDX-License-Identifier: GPL-2.0 +// Copyright (C) 2021 Miroslav Benes mbenes@suse.cz + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include <linux/module.h> +#include <linux/kernel.h> +#include <linux/debugfs.h> +#include <linux/delay.h> + +static int sleep_length = 10000; +module_param(sleep_length, int, 0644); +MODULE_PARM_DESC(sleep_length, "length of sleep in seconds (default=10)"); + +static noinline void child_function(void) +{ + pr_info("%s enter\n", __func__); + msleep(sleep_length); + pr_info("%s exit\n", __func__); +} + +static noinline void child2_function(void) +{ + pr_info("%s\n", __func__); +} + +static noinline void parent_function(void) +{ + pr_info("%s enter\n", __func__); + child_function(); + child2_function(); + pr_info("%s exit\n", __func__); +} + +static int parent_function_get(void *data, u64 *val) +{ + *val = 0; + parent_function(); + + return 0; +} + +DEFINE_DEBUGFS_ATTRIBUTE(fops_parent_function, parent_function_get, NULL, "%llu\n"); + +static struct dentry *debugfs_dir; + +static int test_klp_funcstack_mod_init(void) +{ + struct dentry *d; + + debugfs_dir = debugfs_create_dir("test_klp_funcstack", NULL); + if (IS_ERR(debugfs_dir)) + return PTR_ERR(debugfs_dir); + + d = debugfs_create_file("parent_function", 0400, debugfs_dir, NULL, + &fops_parent_function); + if (IS_ERR(d)) + debugfs_remove_recursive(debugfs_dir); + + return 0; +} + +static void test_klp_funcstack_mod_exit(void) +{ + debugfs_remove_recursive(debugfs_dir); +} + +module_init(test_klp_funcstack_mod_init); +module_exit(test_klp_funcstack_mod_exit); +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Miroslav Benes mbenes@suse.cz"); +MODULE_DESCRIPTION("Livepatch test: func_stack module"); diff --git a/tools/testing/selftests/livepatch/Makefile b/tools/testing/selftests/livepatch/Makefile index 1acc9e1fa3fb..40f8a3a2e9aa 100644 --- a/tools/testing/selftests/livepatch/Makefile +++ b/tools/testing/selftests/livepatch/Makefile @@ -6,7 +6,8 @@ TEST_PROGS := \ test-callbacks.sh \ test-shadow-vars.sh \ test-state.sh \ - test-ftrace.sh + test-ftrace.sh \ + test-func-stack.sh
TEST_FILES := settings
diff --git a/tools/testing/selftests/livepatch/test-func-stack.sh b/tools/testing/selftests/livepatch/test-func-stack.sh new file mode 100755 index 000000000000..b7da62c9f5a1 --- /dev/null +++ b/tools/testing/selftests/livepatch/test-func-stack.sh @@ -0,0 +1,88 @@ +#!/bin/bash +# SPDX-License-Identifier: GPL-2.0 +# Copyright (C) 2021 Miroslav Benes mbenes@suse.cz + +. $(dirname $0)/functions.sh + +MOD_TARGET=test_klp_funcstack_mod +MOD_LIVEPATCH=test_klp_funcstack_demo + +setup_config + +# - load a target module and call its parent_function(). It will sleep in its +# child_function() callee. +# - load a live patch with new child2_function() called from parent_function() +# too. The patching does not wait for child_function() to return, because +# child2_function() is not on any stack. +# - clean up afterwards + +start_test "non-blocking patching without the function on a stack" + +load_mod $MOD_TARGET + +(cat /sys/kernel/debug/test_klp_funcstack/parent_function) >/dev/null & +PID=$! + +load_lp $MOD_LIVEPATCH + +wait $PID + +disable_lp $MOD_LIVEPATCH +unload_lp $MOD_LIVEPATCH +unload_mod $MOD_TARGET + +check_result "% modprobe $MOD_TARGET +$MOD_TARGET: parent_function enter +$MOD_TARGET: child_function enter +% modprobe $MOD_LIVEPATCH +livepatch: enabling patch '$MOD_LIVEPATCH' +livepatch: '$MOD_LIVEPATCH': initializing patching transition +livepatch: '$MOD_LIVEPATCH': starting patching transition +livepatch: '$MOD_LIVEPATCH': completing patching transition +livepatch: '$MOD_LIVEPATCH': patching complete +$MOD_TARGET: child_function exit +$MOD_LIVEPATCH: livepatch_child2_function +$MOD_TARGET: parent_function exit +% echo 0 > /sys/kernel/livepatch/$MOD_LIVEPATCH/enabled +livepatch: '$MOD_LIVEPATCH': initializing unpatching transition +livepatch: '$MOD_LIVEPATCH': starting unpatching transition +livepatch: '$MOD_LIVEPATCH': completing unpatching transition +livepatch: '$MOD_LIVEPATCH': unpatching complete +% rmmod $MOD_LIVEPATCH +% rmmod $MOD_TARGET" + +# Similar to the previous test but now the patching has to wait for +# child2_function() to return, because parent_function() is also checked for. + +start_test "patching delayed due to the function on a stack" + +load_mod $MOD_TARGET + +(cat /sys/kernel/debug/test_klp_funcstack/parent_function) >/dev/null & + +load_lp $MOD_LIVEPATCH funcstack=1 +disable_lp $MOD_LIVEPATCH +unload_lp $MOD_LIVEPATCH +unload_mod $MOD_TARGET + +check_result "% modprobe $MOD_TARGET +$MOD_TARGET: parent_function enter +$MOD_TARGET: child_function enter +% modprobe $MOD_LIVEPATCH funcstack=1 +livepatch: enabling patch '$MOD_LIVEPATCH' +livepatch: '$MOD_LIVEPATCH': initializing patching transition +livepatch: '$MOD_LIVEPATCH': starting patching transition +$MOD_TARGET: child_function exit +$MOD_TARGET: child2_function +$MOD_TARGET: parent_function exit +livepatch: '$MOD_LIVEPATCH': completing patching transition +livepatch: '$MOD_LIVEPATCH': patching complete +% echo 0 > /sys/kernel/livepatch/$MOD_LIVEPATCH/enabled +livepatch: '$MOD_LIVEPATCH': initializing unpatching transition +livepatch: '$MOD_LIVEPATCH': starting unpatching transition +livepatch: '$MOD_LIVEPATCH': completing unpatching transition +livepatch: '$MOD_LIVEPATCH': unpatching complete +% rmmod $MOD_LIVEPATCH +% rmmod $MOD_TARGET" + +exit 0