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livepatch: Selftests of the API for tracking system state changes
Four selftests for the new API. Link: http://lkml.kernel.org/r/[email protected] To: Jiri Kosina <[email protected]> Cc: Kamalesh Babulal <[email protected]> Cc: Nicolai Stange <[email protected]> Cc: [email protected] Cc: [email protected] Acked-by: Miroslav Benes <[email protected]> Acked-by: Joe Lawrence <[email protected]> Acked-by: Josh Poimboeuf <[email protected]> Signed-off-by: Petr Mladek <[email protected]>
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‎lib/livepatch/Makefile

Lines changed: 4 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -8,7 +8,10 @@ obj-$(CONFIG_TEST_LIVEPATCH) += test_klp_atomic_replace.o \
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test_klp_callbacks_busy.o \
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test_klp_callbacks_mod.o \
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test_klp_livepatch.o \
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test_klp_shadow_vars.o
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test_klp_shadow_vars.o \
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test_klp_state.o \
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test_klp_state2.o \
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test_klp_state3.o
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# Target modules to be livepatched require CC_FLAGS_FTRACE
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CFLAGS_test_klp_callbacks_busy.o += $(CC_FLAGS_FTRACE)

‎lib/livepatch/test_klp_state.c

Lines changed: 162 additions & 0 deletions
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@@ -0,0 +1,162 @@
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// SPDX-License-Identifier: GPL-2.0
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// Copyright (C) 2019 SUSE
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/slab.h>
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#include <linux/module.h>
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#include <linux/kernel.h>
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#include <linux/printk.h>
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#include <linux/livepatch.h>
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#define CONSOLE_LOGLEVEL_STATE 1
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/* Version 1 does not support migration. */
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#define CONSOLE_LOGLEVEL_STATE_VERSION 1
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static const char *const module_state[] = {
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[MODULE_STATE_LIVE] = "[MODULE_STATE_LIVE] Normal state",
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[MODULE_STATE_COMING] = "[MODULE_STATE_COMING] Full formed, running module_init",
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[MODULE_STATE_GOING] = "[MODULE_STATE_GOING] Going away",
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[MODULE_STATE_UNFORMED] = "[MODULE_STATE_UNFORMED] Still setting it up",
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};
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static void callback_info(const char *callback, struct klp_object *obj)
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{
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if (obj->mod)
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pr_info("%s: %s -> %s\n", callback, obj->mod->name,
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module_state[obj->mod->state]);
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else
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pr_info("%s: vmlinux\n", callback);
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}
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static struct klp_patch patch;
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static int allocate_loglevel_state(void)
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{
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struct klp_state *loglevel_state;
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loglevel_state = klp_get_state(&patch, CONSOLE_LOGLEVEL_STATE);
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if (!loglevel_state)
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return -EINVAL;
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loglevel_state->data = kzalloc(sizeof(console_loglevel), GFP_KERNEL);
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if (!loglevel_state->data)
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return -ENOMEM;
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pr_info("%s: allocating space to store console_loglevel\n",
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__func__);
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return 0;
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}
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static void fix_console_loglevel(void)
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{
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struct klp_state *loglevel_state;
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loglevel_state = klp_get_state(&patch, CONSOLE_LOGLEVEL_STATE);
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if (!loglevel_state)
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return;
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pr_info("%s: fixing console_loglevel\n", __func__);
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*(int *)loglevel_state->data = console_loglevel;
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console_loglevel = CONSOLE_LOGLEVEL_MOTORMOUTH;
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}
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static void restore_console_loglevel(void)
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{
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struct klp_state *loglevel_state;
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loglevel_state = klp_get_state(&patch, CONSOLE_LOGLEVEL_STATE);
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if (!loglevel_state)
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return;
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pr_info("%s: restoring console_loglevel\n", __func__);
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console_loglevel = *(int *)loglevel_state->data;
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}
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static void free_loglevel_state(void)
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{
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struct klp_state *loglevel_state;
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loglevel_state = klp_get_state(&patch, CONSOLE_LOGLEVEL_STATE);
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if (!loglevel_state)
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return;
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pr_info("%s: freeing space for the stored console_loglevel\n",
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__func__);
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kfree(loglevel_state->data);
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}
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/* Executed on object patching (ie, patch enablement) */
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static int pre_patch_callback(struct klp_object *obj)
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{
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callback_info(__func__, obj);
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return allocate_loglevel_state();
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}
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/* Executed on object unpatching (ie, patch disablement) */
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static void post_patch_callback(struct klp_object *obj)
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{
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callback_info(__func__, obj);
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fix_console_loglevel();
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}
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/* Executed on object unpatching (ie, patch disablement) */
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static void pre_unpatch_callback(struct klp_object *obj)
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{
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callback_info(__func__, obj);
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restore_console_loglevel();
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}
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/* Executed on object unpatching (ie, patch disablement) */
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static void post_unpatch_callback(struct klp_object *obj)
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{
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callback_info(__func__, obj);
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free_loglevel_state();
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}
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static struct klp_func no_funcs[] = {
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{}
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};
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static struct klp_object objs[] = {
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{
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.name = NULL, /* vmlinux */
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.funcs = no_funcs,
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.callbacks = {
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.pre_patch = pre_patch_callback,
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.post_patch = post_patch_callback,
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.pre_unpatch = pre_unpatch_callback,
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.post_unpatch = post_unpatch_callback,
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},
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}, { }
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};
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static struct klp_state states[] = {
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{
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.id = CONSOLE_LOGLEVEL_STATE,
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.version = CONSOLE_LOGLEVEL_STATE_VERSION,
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}, { }
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};
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static struct klp_patch patch = {
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.mod = THIS_MODULE,
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.objs = objs,
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.states = states,
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.replace = true,
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};
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static int test_klp_callbacks_demo_init(void)
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{
150+
return klp_enable_patch(&patch);
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}
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static void test_klp_callbacks_demo_exit(void)
154+
{
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}
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module_init(test_klp_callbacks_demo_init);
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module_exit(test_klp_callbacks_demo_exit);
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MODULE_LICENSE("GPL");
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MODULE_INFO(livepatch, "Y");
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MODULE_AUTHOR("Petr Mladek <[email protected]>");
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MODULE_DESCRIPTION("Livepatch test: system state modification");

‎lib/livepatch/test_klp_state2.c

Lines changed: 191 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,191 @@
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// SPDX-License-Identifier: GPL-2.0
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// Copyright (C) 2019 SUSE
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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6+
#include <linux/slab.h>
7+
#include <linux/module.h>
8+
#include <linux/kernel.h>
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#include <linux/printk.h>
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#include <linux/livepatch.h>
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#define CONSOLE_LOGLEVEL_STATE 1
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/* Version 2 supports migration. */
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#define CONSOLE_LOGLEVEL_STATE_VERSION 2
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static const char *const module_state[] = {
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[MODULE_STATE_LIVE] = "[MODULE_STATE_LIVE] Normal state",
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[MODULE_STATE_COMING] = "[MODULE_STATE_COMING] Full formed, running module_init",
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[MODULE_STATE_GOING] = "[MODULE_STATE_GOING] Going away",
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[MODULE_STATE_UNFORMED] = "[MODULE_STATE_UNFORMED] Still setting it up",
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};
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static void callback_info(const char *callback, struct klp_object *obj)
24+
{
25+
if (obj->mod)
26+
pr_info("%s: %s -> %s\n", callback, obj->mod->name,
27+
module_state[obj->mod->state]);
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else
29+
pr_info("%s: vmlinux\n", callback);
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}
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static struct klp_patch patch;
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static int allocate_loglevel_state(void)
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{
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struct klp_state *loglevel_state, *prev_loglevel_state;
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prev_loglevel_state = klp_get_prev_state(CONSOLE_LOGLEVEL_STATE);
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if (prev_loglevel_state) {
40+
pr_info("%s: space to store console_loglevel already allocated\n",
41+
__func__);
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return 0;
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}
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loglevel_state = klp_get_state(&patch, CONSOLE_LOGLEVEL_STATE);
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if (!loglevel_state)
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return -EINVAL;
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loglevel_state->data = kzalloc(sizeof(console_loglevel), GFP_KERNEL);
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if (!loglevel_state->data)
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return -ENOMEM;
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pr_info("%s: allocating space to store console_loglevel\n",
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__func__);
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return 0;
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}
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static void fix_console_loglevel(void)
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{
60+
struct klp_state *loglevel_state, *prev_loglevel_state;
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loglevel_state = klp_get_state(&patch, CONSOLE_LOGLEVEL_STATE);
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if (!loglevel_state)
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return;
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prev_loglevel_state = klp_get_prev_state(CONSOLE_LOGLEVEL_STATE);
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if (prev_loglevel_state) {
68+
pr_info("%s: taking over the console_loglevel change\n",
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__func__);
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loglevel_state->data = prev_loglevel_state->data;
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return;
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}
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pr_info("%s: fixing console_loglevel\n", __func__);
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*(int *)loglevel_state->data = console_loglevel;
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console_loglevel = CONSOLE_LOGLEVEL_MOTORMOUTH;
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}
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static void restore_console_loglevel(void)
80+
{
81+
struct klp_state *loglevel_state, *prev_loglevel_state;
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prev_loglevel_state = klp_get_prev_state(CONSOLE_LOGLEVEL_STATE);
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if (prev_loglevel_state) {
85+
pr_info("%s: passing the console_loglevel change back to the old livepatch\n",
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__func__);
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return;
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}
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loglevel_state = klp_get_state(&patch, CONSOLE_LOGLEVEL_STATE);
91+
if (!loglevel_state)
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return;
93+
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pr_info("%s: restoring console_loglevel\n", __func__);
95+
console_loglevel = *(int *)loglevel_state->data;
96+
}
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static void free_loglevel_state(void)
99+
{
100+
struct klp_state *loglevel_state, *prev_loglevel_state;
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prev_loglevel_state = klp_get_prev_state(CONSOLE_LOGLEVEL_STATE);
103+
if (prev_loglevel_state) {
104+
pr_info("%s: keeping space to store console_loglevel\n",
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__func__);
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return;
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}
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loglevel_state = klp_get_state(&patch, CONSOLE_LOGLEVEL_STATE);
110+
if (!loglevel_state)
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return;
112+
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pr_info("%s: freeing space for the stored console_loglevel\n",
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__func__);
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kfree(loglevel_state->data);
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}
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/* Executed on object patching (ie, patch enablement) */
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static int pre_patch_callback(struct klp_object *obj)
120+
{
121+
callback_info(__func__, obj);
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return allocate_loglevel_state();
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}
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/* Executed on object unpatching (ie, patch disablement) */
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static void post_patch_callback(struct klp_object *obj)
127+
{
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callback_info(__func__, obj);
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fix_console_loglevel();
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}
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/* Executed on object unpatching (ie, patch disablement) */
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static void pre_unpatch_callback(struct klp_object *obj)
134+
{
135+
callback_info(__func__, obj);
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restore_console_loglevel();
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}
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/* Executed on object unpatching (ie, patch disablement) */
140+
static void post_unpatch_callback(struct klp_object *obj)
141+
{
142+
callback_info(__func__, obj);
143+
free_loglevel_state();
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}
145+
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static struct klp_func no_funcs[] = {
147+
{}
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};
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static struct klp_object objs[] = {
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{
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.name = NULL, /* vmlinux */
153+
.funcs = no_funcs,
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.callbacks = {
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.pre_patch = pre_patch_callback,
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.post_patch = post_patch_callback,
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.pre_unpatch = pre_unpatch_callback,
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.post_unpatch = post_unpatch_callback,
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},
160+
}, { }
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};
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static struct klp_state states[] = {
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{
165+
.id = CONSOLE_LOGLEVEL_STATE,
166+
.version = CONSOLE_LOGLEVEL_STATE_VERSION,
167+
}, { }
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};
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static struct klp_patch patch = {
171+
.mod = THIS_MODULE,
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.objs = objs,
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.states = states,
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.replace = true,
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};
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static int test_klp_callbacks_demo_init(void)
178+
{
179+
return klp_enable_patch(&patch);
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}
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static void test_klp_callbacks_demo_exit(void)
183+
{
184+
}
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module_init(test_klp_callbacks_demo_init);
187+
module_exit(test_klp_callbacks_demo_exit);
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MODULE_LICENSE("GPL");
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MODULE_INFO(livepatch, "Y");
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MODULE_AUTHOR("Petr Mladek <[email protected]>");
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MODULE_DESCRIPTION("Livepatch test: system state modification");

‎lib/livepatch/test_klp_state3.c

Lines changed: 5 additions & 0 deletions
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@@ -0,0 +1,5 @@
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// SPDX-License-Identifier: GPL-2.0
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// Copyright (C) 2019 SUSE
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/* The console loglevel fix is the same in the next cumulative patch. */
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#include "test_klp_state2.c"

‎tools/testing/selftests/livepatch/Makefile

Lines changed: 2 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -4,6 +4,7 @@ TEST_PROGS_EXTENDED := functions.sh
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TEST_PROGS := \
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test-livepatch.sh \
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test-callbacks.sh \
7-
test-shadow-vars.sh
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test-shadow-vars.sh \
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test-state.sh
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include ../lib.mk

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