[PATCH v3 6/7] selftests/livepatch: Add test for state ID conflict across replace_sets

[Yafang Shao <laoar.shao@gmail.com>]

Livepatches with different replace_sets must not share the same state
ID. If a second livepatch attempts to reuse a state ID already
registered by a livepatch with a different replace_set, the loading
will fail.

Add a test case to verify this behavior. The test result is as follows:

$ ./test-state.sh
TEST: system state modification ... ok
TEST: taking over system state modification ... ok
TEST: compatible cumulative livepatches ... ok
TEST: incompatible cumulative livepatches ... ok
TEST: livepatches state compatibility  ... ok    <<<< This case

Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
---
 .../testing/selftests/livepatch/test-state.sh |  34 ++++
 .../selftests/livepatch/test_modules/Makefile |   1 +
 .../livepatch/test_modules/test_klp_state.c   |   2 +-
 .../livepatch/test_modules/test_klp_state2.c  |   2 +-
 .../livepatch/test_modules/test_klp_state4.c  | 163 ++++++++++++++++++
 5 files changed, 200 insertions(+), 2 deletions(-)
 create mode 100644 tools/testing/selftests/livepatch/test_modules/test_klp_state4.c

diff --git a/tools/testing/selftests/livepatch/test-state.sh b/tools/testing/selftests/livepatch/test-state.sh
index 04b66380f8a0..934a2aa655bb 100755
--- a/tools/testing/selftests/livepatch/test-state.sh
+++ b/tools/testing/selftests/livepatch/test-state.sh
@@ -7,6 +7,7 @@
 MOD_LIVEPATCH=test_klp_state
 MOD_LIVEPATCH2=test_klp_state2
 MOD_LIVEPATCH3=test_klp_state3
+MOD_LIVEPATCH4=test_klp_state4
 
 setup_config
 
@@ -173,4 +174,37 @@ $MOD_LIVEPATCH2: free_loglevel_state: freeing space for the stored console_logle
 livepatch: '$MOD_LIVEPATCH2': unpatching complete
 % rmmod $MOD_LIVEPATCH2"
 
+# livepatches with different replace_set sharing the same state ID
+
+start_test "livepatches state compatibility "
+
+load_lp $MOD_LIVEPATCH
+load_failing_mod $MOD_LIVEPATCH4
+disable_lp $MOD_LIVEPATCH
+unload_lp $MOD_LIVEPATCH
+
+check_result "% insmod test_modules/$MOD_LIVEPATCH.ko
+livepatch: enabling patch '$MOD_LIVEPATCH'
+livepatch: '$MOD_LIVEPATCH': initializing patching transition
+$MOD_LIVEPATCH: pre_patch_callback: vmlinux
+$MOD_LIVEPATCH: allocate_loglevel_state: allocating space to store console_loglevel
+livepatch: '$MOD_LIVEPATCH': starting patching transition
+livepatch: '$MOD_LIVEPATCH': completing patching transition
+$MOD_LIVEPATCH: post_patch_callback: vmlinux
+$MOD_LIVEPATCH: fix_console_loglevel: fixing console_loglevel
+livepatch: '$MOD_LIVEPATCH': patching complete
+% insmod test_modules/$MOD_LIVEPATCH4.ko
+livepatch: Livepatch patch ($MOD_LIVEPATCH4) is not compatible with the already installed livepatches.
+insmod: ERROR: could not insert module test_modules/$MOD_LIVEPATCH4.ko: Invalid parameters
+% echo 0 > $SYSFS_KLP_DIR/$MOD_LIVEPATCH/enabled
+livepatch: '$MOD_LIVEPATCH': initializing unpatching transition
+$MOD_LIVEPATCH: pre_unpatch_callback: vmlinux
+$MOD_LIVEPATCH: restore_console_loglevel: restoring console_loglevel
+livepatch: '$MOD_LIVEPATCH': starting unpatching transition
+livepatch: '$MOD_LIVEPATCH': completing unpatching transition
+$MOD_LIVEPATCH: post_unpatch_callback: vmlinux
+$MOD_LIVEPATCH: free_loglevel_state: freeing space for the stored console_loglevel
+livepatch: '$MOD_LIVEPATCH': unpatching complete
+% rmmod $MOD_LIVEPATCH"
+
 exit 0
diff --git a/tools/testing/selftests/livepatch/test_modules/Makefile b/tools/testing/selftests/livepatch/test_modules/Makefile
index a13d398585dc..bdc5ae37311e 100644
--- a/tools/testing/selftests/livepatch/test_modules/Makefile
+++ b/tools/testing/selftests/livepatch/test_modules/Makefile
@@ -14,6 +14,7 @@ obj-m += test_klp_atomic_replace.o \
 	test_klp_state.o \
 	test_klp_state2.o \
 	test_klp_state3.o \
+	test_klp_state4.o \
 	test_klp_syscall.o
 
 # Ensure that KDIR exists, otherwise skip the compilation
diff --git a/tools/testing/selftests/livepatch/test_modules/test_klp_state.c b/tools/testing/selftests/livepatch/test_modules/test_klp_state.c
index 8c8829c3ec43..6ef3059483de 100644
--- a/tools/testing/selftests/livepatch/test_modules/test_klp_state.c
+++ b/tools/testing/selftests/livepatch/test_modules/test_klp_state.c
@@ -39,7 +39,7 @@ static int allocate_loglevel_state(void)
 	if (!loglevel_state)
 		return -EINVAL;
 
-	loglevel_state->data = kzalloc(sizeof(console_loglevel), GFP_KERNEL);
+	loglevel_state->data = kzalloc_obj(console_loglevel, GFP_KERNEL);
 	if (!loglevel_state->data)
 		return -ENOMEM;
 
diff --git a/tools/testing/selftests/livepatch/test_modules/test_klp_state2.c b/tools/testing/selftests/livepatch/test_modules/test_klp_state2.c
index 8a79d7dcce33..908d79bc7540 100644
--- a/tools/testing/selftests/livepatch/test_modules/test_klp_state2.c
+++ b/tools/testing/selftests/livepatch/test_modules/test_klp_state2.c
@@ -46,7 +46,7 @@ static int allocate_loglevel_state(void)
 	if (!loglevel_state)
 		return -EINVAL;
 
-	loglevel_state->data = kzalloc(sizeof(console_loglevel), GFP_KERNEL);
+	loglevel_state->data = kzalloc_obj(console_loglevel, GFP_KERNEL);
 	if (!loglevel_state->data)
 		return -ENOMEM;
 
diff --git a/tools/testing/selftests/livepatch/test_modules/test_klp_state4.c b/tools/testing/selftests/livepatch/test_modules/test_klp_state4.c
new file mode 100644
index 000000000000..010d1e13f6ec
--- /dev/null
+++ b/tools/testing/selftests/livepatch/test_modules/test_klp_state4.c
@@ -0,0 +1,163 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * This test is identical to test_klp_state4.c, except that replace_set is
+ * set to 4 instead of 0.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/printk.h>
+#include <linux/livepatch.h>
+
+#define CONSOLE_LOGLEVEL_STATE 1
+#define CONSOLE_LOGLEVEL_STATE_VERSION 4
+
+static const char *const module_state[] = {
+	[MODULE_STATE_LIVE]	= "[MODULE_STATE_LIVE] Normal state",
+	[MODULE_STATE_COMING]	= "[MODULE_STATE_COMING] Full formed, running module_init",
+	[MODULE_STATE_GOING]	= "[MODULE_STATE_GOING] Going away",
+	[MODULE_STATE_UNFORMED]	= "[MODULE_STATE_UNFORMED] Still setting it up",
+};
+
+static void callback_info(const char *callback, struct klp_object *obj)
+{
+	if (obj->mod)
+		pr_info("%s: %s -> %s\n", callback, obj->mod->name,
+			module_state[obj->mod->state]);
+	else
+		pr_info("%s: vmlinux\n", callback);
+}
+
+static struct klp_patch patch;
+
+static int allocate_loglevel_state(void)
+{
+	struct klp_state *loglevel_state;
+
+	loglevel_state = klp_get_state(&patch, CONSOLE_LOGLEVEL_STATE);
+	if (!loglevel_state)
+		return -EINVAL;
+
+	loglevel_state->data = kzalloc_obj(console_loglevel, GFP_KERNEL);
+	if (!loglevel_state->data)
+		return -ENOMEM;
+
+	pr_info("%s: allocating space to store console_loglevel\n",
+		__func__);
+	return 0;
+}
+
+static void fix_console_loglevel(void)
+{
+	struct klp_state *loglevel_state;
+
+	loglevel_state = klp_get_state(&patch, CONSOLE_LOGLEVEL_STATE);
+	if (!loglevel_state)
+		return;
+
+	pr_info("%s: fixing console_loglevel\n", __func__);
+	*(int *)loglevel_state->data = console_loglevel;
+	console_loglevel = CONSOLE_LOGLEVEL_MOTORMOUTH;
+}
+
+static void restore_console_loglevel(void)
+{
+	struct klp_state *loglevel_state;
+
+	loglevel_state = klp_get_state(&patch, CONSOLE_LOGLEVEL_STATE);
+	if (!loglevel_state)
+		return;
+
+	pr_info("%s: restoring console_loglevel\n", __func__);
+	console_loglevel = *(int *)loglevel_state->data;
+}
+
+static void free_loglevel_state(void)
+{
+	struct klp_state *loglevel_state;
+
+	loglevel_state = klp_get_state(&patch, CONSOLE_LOGLEVEL_STATE);
+	if (!loglevel_state)
+		return;
+
+	pr_info("%s: freeing space for the stored console_loglevel\n",
+		__func__);
+	kfree(loglevel_state->data);
+}
+
+/* Executed on object patching (ie, patch enablement) */
+static int pre_patch_callback(struct klp_object *obj)
+{
+	callback_info(__func__, obj);
+	return allocate_loglevel_state();
+}
+
+/* Executed on object unpatching (ie, patch disablement) */
+static void post_patch_callback(struct klp_object *obj)
+{
+	callback_info(__func__, obj);
+	fix_console_loglevel();
+}
+
+/* Executed on object unpatching (ie, patch disablement) */
+static void pre_unpatch_callback(struct klp_object *obj)
+{
+	callback_info(__func__, obj);
+	restore_console_loglevel();
+}
+
+/* Executed on object unpatching (ie, patch disablement) */
+static void post_unpatch_callback(struct klp_object *obj)
+{
+	callback_info(__func__, obj);
+	free_loglevel_state();
+}
+
+static struct klp_func no_funcs[] = {
+	{}
+};
+
+static struct klp_object objs[] = {
+	{
+		.name = NULL,	/* vmlinux */
+		.funcs = no_funcs,
+		.callbacks = {
+			.pre_patch = pre_patch_callback,
+			.post_patch = post_patch_callback,
+			.pre_unpatch = pre_unpatch_callback,
+			.post_unpatch = post_unpatch_callback,
+		},
+	}, { }
+};
+
+static struct klp_state states[] = {
+	{
+		.id = CONSOLE_LOGLEVEL_STATE,
+		.version = CONSOLE_LOGLEVEL_STATE_VERSION,
+	}, { }
+};
+
+static struct klp_patch patch = {
+	.mod = THIS_MODULE,
+	.objs = objs,
+	.states = states,
+	.replace_set = 4,
+};
+
+static int test_klp_callbacks_demo_init(void)
+{
+	return klp_enable_patch(&patch);
+}
+
+static void test_klp_callbacks_demo_exit(void)
+{
+}
+
+module_init(test_klp_callbacks_demo_init);
+module_exit(test_klp_callbacks_demo_exit);
+MODULE_LICENSE("GPL");
+MODULE_INFO(livepatch, "Y");
+MODULE_DESCRIPTION("Livepatch test: system state compatibility verification");
-- 
2.52.0