module: make it clear when we're handling the module copy in info->hdr

In load_module(), it's not always clear whether we're handling the
temporary module copy in info->hdr (which is freed at the end of
load_module()) or if we're handling the module already allocated and
copied to it's final place. Adding an info->mod field and using it
whenever we're handling the temporary copy makes that explicitly clear.

Signed-off-by: Jessica Yu <jeyu@kernel.org>

diff --git a/kernel/module.c b/kernel/module.c
index 4a6b9c6..3ed4aaa 100644 (file)
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -309,6 +309,8 @@ EXPORT_SYMBOL(unregister_module_notifier);
 
 struct load_info {
        const char *name;
+       /* pointer to module in temporary copy, freed at end of load_module() */
+       struct module *mod;
        Elf_Ehdr *hdr;
        unsigned long len;
        Elf_Shdr *sechdrs;
@@ -2947,14 +2949,13 @@ static int rewrite_section_headers(struct load_info *info, int flags)
  * search for module section index etc), and do some basic section
  * verification.
  *
- * Return the temporary module pointer (we'll replace it with the final
- * one when we move the module sections around).
+ * Set info->mod to the temporary copy of the module in info->hdr. The final one
+ * will be allocated in move_module().
  */
-static struct module *setup_load_info(struct load_info *info, int flags)
+static int setup_load_info(struct load_info *info, int flags)
 {
        unsigned int i;
        int err;
-       struct module *mod;
 
        /* Set up the convenience variables */
        info->sechdrs = (void *)info->hdr + info->hdr->e_shoff;
@@ -2963,7 +2964,7 @@ static struct module *setup_load_info(struct load_info *info, int flags)
 
        err = rewrite_section_headers(info, flags);
        if (err)
-               return ERR_PTR(err);
+               return err;
 
        /* Find internal symbols and strings. */
        for (i = 1; i < info->hdr->e_shnum; i++) {
@@ -2980,30 +2981,30 @@ static struct module *setup_load_info(struct load_info *info, int flags)
        if (!info->index.mod) {
                pr_warn("%s: No module found in object\n",
                        info->name ?: "(missing .modinfo name field)");
-               return ERR_PTR(-ENOEXEC);
+               return -ENOEXEC;
        }
        /* This is temporary: point mod into copy of data. */
-       mod = (void *)info->sechdrs[info->index.mod].sh_addr;
+       info->mod = (void *)info->sechdrs[info->index.mod].sh_addr;
 
        /*
         * If we didn't load the .modinfo 'name' field, fall back to
         * on-disk struct mod 'name' field.
         */
        if (!info->name)
-               info->name = mod->name;
+               info->name = info->mod->name;
 
        if (info->index.sym == 0) {
                pr_warn("%s: module has no symbols (stripped?)\n", info->name);
-               return ERR_PTR(-ENOEXEC);
+               return -ENOEXEC;
        }
 
        info->index.pcpu = find_pcpusec(info);
 
        /* Check module struct version now, before we try to use module. */
-       if (!check_modstruct_version(info, mod))
-               return ERR_PTR(-ENOEXEC);
+       if (!check_modstruct_version(info, info->mod))
+               return -ENOEXEC;
 
-       return mod;
+       return 0;
 }
 
 static int check_modinfo(struct module *mod, struct load_info *info, int flags)
@@ -3298,25 +3299,24 @@ core_param(module_blacklist, module_blacklist, charp, 0400);
 
 static struct module *layout_and_allocate(struct load_info *info, int flags)
 {
-       /* Module within temporary copy. */
        struct module *mod;
        unsigned int ndx;
        int err;
 
-       mod = setup_load_info(info, flags);
-       if (IS_ERR(mod))
-               return mod;
+       err = setup_load_info(info, flags);
+       if (err)
+               return ERR_PTR(err);
 
        if (blacklisted(info->name))
                return ERR_PTR(-EPERM);
 
-       err = check_modinfo(mod, info, flags);
+       err = check_modinfo(info->mod, info, flags);
        if (err)
                return ERR_PTR(err);
 
        /* Allow arches to frob section contents and sizes.  */
        err = module_frob_arch_sections(info->hdr, info->sechdrs,
-                                       info->secstrings, mod);
+                                       info->secstrings, info->mod);
        if (err < 0)
                return ERR_PTR(err);
 
@@ -3335,11 +3335,11 @@ static struct module *layout_and_allocate(struct load_info *info, int flags)
        /* Determine total sizes, and put offsets in sh_entsize.  For now
           this is done generically; there doesn't appear to be any
           special cases for the architectures. */
-       layout_sections(mod, info);
-       layout_symtab(mod, info);
+       layout_sections(info->mod, info);
+       layout_symtab(info->mod, info);
 
        /* Allocate and move to the final place */
-       err = move_module(mod, info);
+       err = move_module(info->mod, info);
        if (err)
                return ERR_PTR(err);