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()

4 files changed, 52 insertions, 39 deletions

diff --git a/Documentation/ABI/stable/sysfs-module b/Documentation/ABI/stable/sysfs-module
index a0dd21c6db59..6272ae5fb366 100644
--- a/Documentation/ABI/stable/sysfs-module
+++ b/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
diff --git a/include/linux/moduleparam.h b/include/linux/moduleparam.h
index 137b4198fc03..27d9da3f86ff 100644
--- a/include/linux/moduleparam.h
+++ b/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;
 
diff --git a/kernel/module.c b/kernel/module.c
index cab4bce49c23..206915830d29 100644
--- a/kernel/module.c
+++ b/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 @@ out:
         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)
diff --git a/kernel/params.c b/kernel/params.c
index 53b958fcd639..440e65d1a544 100644
--- a/kernel/params.c
+++ b/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.
  *