Modules changes for v6.9-rc1

Christophe Leroy did most of the work on this release, first with a few
 cleanups on CONFIG_STRICT_KERNEL_RWX and ending with error handling for
 when set_memory_XX() can fail. This is part of a larger effort to clean
 up all these callers which can fail, modules is just part of it.
 
 This has been sitting on linux-next for about a month without issues.
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Merge tag 'modules-6.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux

Pull modules updates from Luis Chamberlain:
 "Christophe Leroy did most of the work on this release, first with a
  few cleanups on CONFIG_STRICT_KERNEL_RWX and ending with error
  handling for when set_memory_XX() can fail.

  This is part of a larger effort to clean up all these callers which
  can fail, modules is just part of it"

* tag 'modules-6.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux:
  module: Don't ignore errors from set_memory_XX()
  lib/test_kmod: fix kernel-doc warnings
  powerpc: Simplify strict_kernel_rwx_enabled()
  modules: Remove #ifdef CONFIG_STRICT_MODULE_RWX around rodata_enabled
  init: Declare rodata_enabled and mark_rodata_ro() at all time
  module: Change module_enable_{nx/x/ro}() to more explicit names
  module: Use set_memory_rox()

arch/powerpc/include/asm/mmu.h

@@ -330,17 +330,10 @@ static __always_inline bool early_radix_enabled(void)
 	return early_mmu_has_feature(MMU_FTR_TYPE_RADIX);
 }
 
-#ifdef CONFIG_STRICT_KERNEL_RWX
 static inline bool strict_kernel_rwx_enabled(void)
 {
-	return rodata_enabled;
+	return IS_ENABLED(CONFIG_STRICT_KERNEL_RWX) && rodata_enabled;
 }
-#else
-static inline bool strict_kernel_rwx_enabled(void)
-{
-	return false;
-}
-#endif
 
 static inline bool strict_module_rwx_enabled(void)
 {

include/linux/init.h

@@ -168,12 +168,8 @@ extern initcall_entry_t __initcall_end[];
 
 extern struct file_system_type rootfs_fs_type;
 
-#if defined(CONFIG_STRICT_KERNEL_RWX) || defined(CONFIG_STRICT_MODULE_RWX)
 extern bool rodata_enabled;
-#endif
-#ifdef CONFIG_STRICT_KERNEL_RWX
 void mark_rodata_ro(void);
-#endif
 
 extern void (*late_time_init)(void);
 

init/main.c

@@ -1401,10 +1401,9 @@ static int __init set_debug_rodata(char *str)
 early_param("rodata", set_debug_rodata);
 #endif
 
-#ifdef CONFIG_STRICT_KERNEL_RWX
 static void mark_readonly(void)
 {
-	if (rodata_enabled) {
+	if (IS_ENABLED(CONFIG_STRICT_KERNEL_RWX) && rodata_enabled) {
 		/*
 		 * load_module() results in W+X mappings, which are cleaned
 		 * up with call_rcu().  Let's make sure that queued work is
@@ -1414,20 +1413,14 @@ static void mark_readonly(void)
 		rcu_barrier();
 		mark_rodata_ro();
 		rodata_test();
-	} else
+	} else if (IS_ENABLED(CONFIG_STRICT_KERNEL_RWX)) {
 		pr_info("Kernel memory protection disabled.\n");
+	} else if (IS_ENABLED(CONFIG_ARCH_HAS_STRICT_KERNEL_RWX)) {
+		pr_warn("Kernel memory protection not selected by kernel config.\n");
+	} else {
+		pr_warn("This architecture does not have kernel memory protection.\n");
+	}
 }
-#elif defined(CONFIG_ARCH_HAS_STRICT_KERNEL_RWX)
-static inline void mark_readonly(void)
-{
-	pr_warn("Kernel memory protection not selected by kernel config.\n");
-}
-#else
-static inline void mark_readonly(void)
-{
-	pr_warn("This architecture does not have kernel memory protection.\n");
-}
-#endif
 
 void __weak free_initmem(void)
 {

kernel/module/internal.h

@@ -322,9 +322,9 @@ static inline struct module *mod_find(unsigned long addr, struct mod_tree_root *
 }
 #endif /* CONFIG_MODULES_TREE_LOOKUP */
 
-void module_enable_ro(const struct module *mod, bool after_init);
+int module_enable_rodata_ro(const struct module *mod, bool after_init);
-void module_enable_nx(const struct module *mod);
+int module_enable_data_nx(const struct module *mod);
-void module_enable_x(const struct module *mod);
+int module_enable_text_rox(const struct module *mod);
 int module_enforce_rwx_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs,
 				char *secstrings, struct module *mod);
 

kernel/module/main.c

@@ -2571,7 +2571,9 @@ static noinline int do_init_module(struct module *mod)
 	/* Switch to core kallsyms now init is done: kallsyms may be walking! */
 	rcu_assign_pointer(mod->kallsyms, &mod->core_kallsyms);
 #endif
-	module_enable_ro(mod, true);
+	ret = module_enable_rodata_ro(mod, true);
+	if (ret)
+		goto fail_mutex_unlock;
 	mod_tree_remove_init(mod);
 	module_arch_freeing_init(mod);
 	for_class_mod_mem_type(type, init) {
@@ -2609,6 +2611,8 @@ static noinline int do_init_module(struct module *mod)
 
 	return 0;
 
+fail_mutex_unlock:
+	mutex_unlock(&module_mutex);
 fail_free_freeinit:
 	kfree(freeinit);
 fail:
@@ -2736,9 +2740,15 @@ static int complete_formation(struct module *mod, struct load_info *info)
 	module_bug_finalize(info->hdr, info->sechdrs, mod);
 	module_cfi_finalize(info->hdr, info->sechdrs, mod);
 
-	module_enable_ro(mod, false);
+	err = module_enable_rodata_ro(mod, false);
-	module_enable_nx(mod);
+	if (err)
-	module_enable_x(mod);
+		goto out_strict_rwx;
+	err = module_enable_data_nx(mod);
+	if (err)
+		goto out_strict_rwx;
+	err = module_enable_text_rox(mod);
+	if (err)
+		goto out_strict_rwx;
 
 	/*
 	 * Mark state as coming so strong_try_module_get() ignores us,
@@ -2749,6 +2759,8 @@ static int complete_formation(struct module *mod, struct load_info *info)
 
 	return 0;
 
+out_strict_rwx:
+	module_bug_cleanup(mod);
 out:
 	mutex_unlock(&module_mutex);
 	return err;

kernel/module/strict_rwx.c

@@ -11,13 +11,16 @@
 #include <linux/set_memory.h>
 #include "internal.h"
 
-static void module_set_memory(const struct module *mod, enum mod_mem_type type,
+static int module_set_memory(const struct module *mod, enum mod_mem_type type,
-			      int (*set_memory)(unsigned long start, int num_pages))
+			     int (*set_memory)(unsigned long start, int num_pages))
 {
 	const struct module_memory *mod_mem = &mod->mem[type];
 
+	if (!mod_mem->base)
+		return 0;
+
 	set_vm_flush_reset_perms(mod_mem->base);
-	set_memory((unsigned long)mod_mem->base, mod_mem->size >> PAGE_SHIFT);
+	return set_memory((unsigned long)mod_mem->base, mod_mem->size >> PAGE_SHIFT);
 }
 
 /*
@@ -26,37 +29,53 @@ static void module_set_memory(const struct module *mod, enum mod_mem_type type,
  * CONFIG_STRICT_MODULE_RWX because they are needed regardless of whether we
  * are strict.
  */
-void module_enable_x(const struct module *mod)
+int module_enable_text_rox(const struct module *mod)
 {
-	for_class_mod_mem_type(type, text)
+	for_class_mod_mem_type(type, text) {
-		module_set_memory(mod, type, set_memory_x);
+		int ret;
+
+		if (IS_ENABLED(CONFIG_STRICT_MODULE_RWX))
+			ret = module_set_memory(mod, type, set_memory_rox);
+		else
+			ret = module_set_memory(mod, type, set_memory_x);
+		if (ret)
+			return ret;
+	}
+	return 0;
 }
 
-void module_enable_ro(const struct module *mod, bool after_init)
+int module_enable_rodata_ro(const struct module *mod, bool after_init)
 {
-	if (!IS_ENABLED(CONFIG_STRICT_MODULE_RWX))
+	int ret;
-		return;
-#ifdef CONFIG_STRICT_MODULE_RWX
-	if (!rodata_enabled)
-		return;
-#endif
 
-	module_set_memory(mod, MOD_TEXT, set_memory_ro);
+	if (!IS_ENABLED(CONFIG_STRICT_MODULE_RWX) || !rodata_enabled)
-	module_set_memory(mod, MOD_INIT_TEXT, set_memory_ro);
+		return 0;
-	module_set_memory(mod, MOD_RODATA, set_memory_ro);
+
-	module_set_memory(mod, MOD_INIT_RODATA, set_memory_ro);
+	ret = module_set_memory(mod, MOD_RODATA, set_memory_ro);
+	if (ret)
+		return ret;
+	ret = module_set_memory(mod, MOD_INIT_RODATA, set_memory_ro);
+	if (ret)
+		return ret;
 
 	if (after_init)
-		module_set_memory(mod, MOD_RO_AFTER_INIT, set_memory_ro);
+		return module_set_memory(mod, MOD_RO_AFTER_INIT, set_memory_ro);
+
+	return 0;
 }
 
-void module_enable_nx(const struct module *mod)
+int module_enable_data_nx(const struct module *mod)
 {
 	if (!IS_ENABLED(CONFIG_STRICT_MODULE_RWX))
-		return;
+		return 0;
 
-	for_class_mod_mem_type(type, data)
+	for_class_mod_mem_type(type, data) {
-		module_set_memory(mod, type, set_memory_nx);
+		int ret = module_set_memory(mod, type, set_memory_nx);
+
+		if (ret)
+			return ret;
+	}
+	return 0;
 }
 
 int module_enforce_rwx_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs,

lib/test_kmod.c

@@ -58,11 +58,14 @@ static int num_test_devs;
  * @need_mod_put for your tests case.
  */
 enum kmod_test_case {
+	/* private: */
 	__TEST_KMOD_INVALID = 0,
+	/* public: */
 
 	TEST_KMOD_DRIVER,
 	TEST_KMOD_FS_TYPE,
 
+	/* private: */
 	__TEST_KMOD_MAX,
 };
 
@@ -82,6 +85,7 @@ struct kmod_test_device;
  * @ret_sync: return value if request_module() is used, sync request for
  * 	@TEST_KMOD_DRIVER
  * @fs_sync: return value of get_fs_type() for @TEST_KMOD_FS_TYPE
+ * @task_sync: kthread's task_struct or %NULL if not running
  * @thread_idx: thread ID
  * @test_dev: test device test is being performed under
  * @need_mod_put: Some tests (get_fs_type() is one) requires putting the module
@@ -108,7 +112,7 @@ struct kmod_test_device_info {
  * @dev: pointer to misc_dev's own struct device
  * @config_mutex: protects configuration of test
  * @trigger_mutex: the test trigger can only be fired once at a time
- * @thread_lock: protects @done count, and the @info per each thread
+ * @thread_mutex: protects @done count, and the @info per each thread
  * @done: number of threads which have completed or failed
  * @test_is_oom: when we run out of memory, use this to halt moving forward
  * @kthreads_done: completion used to signal when all work is done