Merge tag 'modules-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux

Pull module updates from Rusty Russell:
 "Nothing interesting.  Except the most embarrassing bugfix ever.  But
  let's ignore that"

* tag 'modules-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux:
  module: cleanup call chain.
  module: do percpu allocation after uniqueness check.  No, really!
  modules: don't fail to load on unknown parameters.
  ABI: Clarify when /sys/module/MODULENAME is created
  There is no /sys/parameters
  module: don't modify argument of module_kallsyms_lookup_name()

Documentation/ABI/stable/sysfs-module

@@ -4,9 +4,13 @@ Description:
 
 	/sys/module/MODULENAME
 		The name of the module that is in the kernel.  This
-		module name will show up either if the module is built
-		directly into the kernel, or if it is loaded as a
-		dynamic module.
+		module name will always show up if the module is loaded as a
+		dynamic module.  If it is built directly into the kernel, it
+		will only show up if it has a version or at least one
+		parameter.
+
+		Note: The conditions of creation in the built-in case are not
+		by design and may be removed in the future.
 
 	/sys/module/MODULENAME/parameters
 		This directory contains individual files that are each

include/linux/moduleparam.h

@@ -439,7 +439,7 @@ extern struct kernel_param_ops param_ops_string;
 extern int param_set_copystring(const char *val, const struct kernel_param *);
 extern int param_get_string(char *buffer, const struct kernel_param *kp);
 
-/* for exporting parameters in /sys/parameters */
+/* for exporting parameters in /sys/module/.../parameters */
 
 struct module;
 

kernel/module.c

@@ -455,7 +455,7 @@ const struct kernel_symbol *find_symbol(const char *name,
 EXPORT_SYMBOL_GPL(find_symbol);
 
 /* Search for module by name: must hold module_mutex. */
-static struct module *find_module_all(const char *name,
+static struct module *find_module_all(const char *name, size_t len,
 				      bool even_unformed)
 {
 	struct module *mod;
@@ -463,7 +463,7 @@ static struct module *find_module_all(const char *name,
 	list_for_each_entry(mod, &modules, list) {
 		if (!even_unformed && mod->state == MODULE_STATE_UNFORMED)
 			continue;
-		if (strcmp(mod->name, name) == 0)
+		if (strlen(mod->name) == len && !memcmp(mod->name, name, len))
 			return mod;
 	}
 	return NULL;
@@ -471,7 +471,7 @@ static struct module *find_module_all(const char *name,
 
 struct module *find_module(const char *name)
 {
-	return find_module_all(name, false);
+	return find_module_all(name, strlen(name), false);
 }
 EXPORT_SYMBOL_GPL(find_module);
 
@@ -482,23 +482,28 @@ static inline void __percpu *mod_percpu(struct module *mod)
 	return mod->percpu;
 }
 
-static int percpu_modalloc(struct module *mod,
-			   unsigned long size, unsigned long align)
+static int percpu_modalloc(struct module *mod, struct load_info *info)
 {
+	Elf_Shdr *pcpusec = &info->sechdrs[info->index.pcpu];
+	unsigned long align = pcpusec->sh_addralign;
+
+	if (!pcpusec->sh_size)
+		return 0;
+
 	if (align > PAGE_SIZE) {
 		printk(KERN_WARNING "%s: per-cpu alignment %li > %li\n",
 		       mod->name, align, PAGE_SIZE);
 		align = PAGE_SIZE;
 	}
 
-	mod->percpu = __alloc_reserved_percpu(size, align);
+	mod->percpu = __alloc_reserved_percpu(pcpusec->sh_size, align);
 	if (!mod->percpu) {
 		printk(KERN_WARNING
 		       "%s: Could not allocate %lu bytes percpu data\n",
-		       mod->name, size);
+		       mod->name, (unsigned long)pcpusec->sh_size);
 		return -ENOMEM;
 	}
-	mod->percpu_size = size;
+	mod->percpu_size = pcpusec->sh_size;
 	return 0;
 }
 
@@ -563,10 +568,12 @@ static inline void __percpu *mod_percpu(struct module *mod)
 {
 	return NULL;
 }
-static inline int percpu_modalloc(struct module *mod,
-				  unsigned long size, unsigned long align)
+static int percpu_modalloc(struct module *mod, struct load_info *info)
 {
-	return -ENOMEM;
+	/* UP modules shouldn't have this section: ENOMEM isn't quite right */
+	if (info->sechdrs[info->index.pcpu].sh_size != 0)
+		return -ENOMEM;
+	return 0;
 }
 static inline void percpu_modfree(struct module *mod)
 {
@@ -2927,7 +2934,6 @@ static struct module *layout_and_allocate(struct load_info *info, int flags)
 {
 	/* Module within temporary copy. */
 	struct module *mod;
-	Elf_Shdr *pcpusec;
 	int err;
 
 	mod = setup_load_info(info, flags);
@@ -2942,17 +2948,10 @@ static struct module *layout_and_allocate(struct load_info *info, int flags)
 	err = module_frob_arch_sections(info->hdr, info->sechdrs,
 					info->secstrings, mod);
 	if (err < 0)
-		goto out;
+		return ERR_PTR(err);
 
-	pcpusec = &info->sechdrs[info->index.pcpu];
-	if (pcpusec->sh_size) {
-		/* We have a special allocation for this section. */
-		err = percpu_modalloc(mod,
-				      pcpusec->sh_size, pcpusec->sh_addralign);
-		if (err)
-			goto out;
-		pcpusec->sh_flags &= ~(unsigned long)SHF_ALLOC;
-	}
+	/* We will do a special allocation for per-cpu sections later. */
+	info->sechdrs[info->index.pcpu].sh_flags &= ~(unsigned long)SHF_ALLOC;
 
 	/* Determine total sizes, and put offsets in sh_entsize.  For now
 	   this is done generically; there doesn't appear to be any
@@ -2963,17 +2962,12 @@ static struct module *layout_and_allocate(struct load_info *info, int flags)
 	/* Allocate and move to the final place */
 	err = move_module(mod, info);
 	if (err)
-		goto free_percpu;
+		return ERR_PTR(err);
 
 	/* Module has been copied to its final place now: return it. */
 	mod = (void *)info->sechdrs[info->index.mod].sh_addr;
 	kmemleak_load_module(mod, info);
 	return mod;
-
-free_percpu:
-	percpu_modfree(mod);
-out:
-	return ERR_PTR(err);
 }
 
 /* mod is no longer valid after this! */
@@ -3014,7 +3008,7 @@ static bool finished_loading(const char *name)
 	bool ret;
 
 	mutex_lock(&module_mutex);
-	mod = find_module_all(name, true);
+	mod = find_module_all(name, strlen(name), true);
 	ret = !mod || mod->state == MODULE_STATE_LIVE
 		|| mod->state == MODULE_STATE_GOING;
 	mutex_unlock(&module_mutex);
@@ -3152,7 +3146,8 @@ static int add_unformed_module(struct module *mod)
 
 again:
 	mutex_lock(&module_mutex);
-	if ((old = find_module_all(mod->name, true)) != NULL) {
+	old = find_module_all(mod->name, strlen(mod->name), true);
+	if (old != NULL) {
 		if (old->state == MODULE_STATE_COMING
 		    || old->state == MODULE_STATE_UNFORMED) {
 			/* Wait in case it fails to load. */
@@ -3198,6 +3193,17 @@ static int complete_formation(struct module *mod, struct load_info *info)
 	return err;
 }
 
+static int unknown_module_param_cb(char *param, char *val, const char *modname)
+{
+	/* Check for magic 'dyndbg' arg */ 
+	int ret = ddebug_dyndbg_module_param_cb(param, val, modname);
+	if (ret != 0) {
+		printk(KERN_WARNING "%s: unknown parameter '%s' ignored\n",
+		       modname, param);
+	}
+	return 0;
+}
+
 /* Allocate and load the module: note that size of section 0 is always
    zero, and we rely on this for optional sections. */
 static int load_module(struct load_info *info, const char __user *uargs,
@@ -3237,6 +3243,11 @@ static int load_module(struct load_info *info, const char __user *uargs,
 	}
 #endif
 
+	/* To avoid stressing percpu allocator, do this once we're unique. */
+	err = percpu_modalloc(mod, info);
+	if (err)
+		goto unlink_mod;
+
 	/* Now module is in final location, initialize linked lists, etc. */
 	err = module_unload_init(mod);
 	if (err)
@@ -3284,7 +3295,7 @@ static int load_module(struct load_info *info, const char __user *uargs,
 
 	/* Module is ready to execute: parsing args may do that. */
 	err = parse_args(mod->name, mod->args, mod->kp, mod->num_kp,
-			 -32768, 32767, &ddebug_dyndbg_module_param_cb);
+			 -32768, 32767, unknown_module_param_cb);
 	if (err < 0)
 		goto bug_cleanup;
 
@@ -3563,10 +3574,8 @@ unsigned long module_kallsyms_lookup_name(const char *name)
 	/* Don't lock: we're in enough trouble already. */
 	preempt_disable();
 	if ((colon = strchr(name, ':')) != NULL) {
-		*colon = '\0';
-		if ((mod = find_module(name)) != NULL)
+		if ((mod = find_module_all(name, colon - name, false)) != NULL)
 			ret = mod_find_symname(mod, colon+1);
-		*colon = ':';
 	} else {
 		list_for_each_entry_rcu(mod, &modules, list) {
 			if (mod->state == MODULE_STATE_UNFORMED)

kernel/params.c

@@ -787,7 +787,7 @@ static void __init kernel_add_sysfs_param(const char *name,
 }
 
 /*
- * param_sysfs_builtin - add contents in /sys/parameters for built-in modules
+ * param_sysfs_builtin - add sysfs parameters for built-in modules
  *
  * Add module_parameters to sysfs for "modules" built into the kernel.
  *