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authorLinus Torvalds <torvalds@linux-foundation.org>2017-07-12 17:22:01 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2017-07-12 17:22:01 -0700
commit3a75ad1457d9cd84bc17d5b9cffb4d73b52be20b (patch)
tree8ca06468b1f9feffeefe04f700264ed7345d7803 /kernel/module.c
parent235b84fc862ae2637dc0dabada18d97f1bfc18e1 (diff)
parent96b5b19459b3c2aed2872bac42cbe19edfae710f (diff)
Merge tag 'modules-for-v4.13' of git://git.kernel.org/pub/scm/linux/kernel/git/jeyu/linux
Pull modules updates from Jessica Yu: "Summary of modules changes for the 4.13 merge window: - Minor code cleanups - Avoid accessing mod struct prior to checking module struct version, from Kees - Fix racy atomic inc/dec logic of kmod_concurrent_max in kmod, from Luis" * tag 'modules-for-v4.13' of git://git.kernel.org/pub/scm/linux/kernel/git/jeyu/linux: module: make the modinfo name const kmod: reduce atomic operations on kmod_concurrent and simplify module: use list_for_each_entry_rcu() on find_module_all() kernel/module.c: suppress warning about unused nowarn variable module: Add module name to modinfo module: Pass struct load_info into symbol checks
Diffstat (limited to 'kernel/module.c')
-rw-r--r--kernel/module.c85
1 files changed, 54 insertions, 31 deletions
diff --git a/kernel/module.c b/kernel/module.c
index b0f92a365140..40f983cbea81 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -300,6 +300,7 @@ int unregister_module_notifier(struct notifier_block *nb)
EXPORT_SYMBOL(unregister_module_notifier);
struct load_info {
+ const char *name;
Elf_Ehdr *hdr;
unsigned long len;
Elf_Shdr *sechdrs;
@@ -600,7 +601,7 @@ static struct module *find_module_all(const char *name, size_t len,
module_assert_mutex_or_preempt();
- list_for_each_entry(mod, &modules, list) {
+ list_for_each_entry_rcu(mod, &modules, list) {
if (!even_unformed && mod->state == MODULE_STATE_UNFORMED)
continue;
if (strlen(mod->name) == len && !memcmp(mod->name, name, len))
@@ -1273,12 +1274,13 @@ static u32 resolve_rel_crc(const s32 *crc)
return *(u32 *)((void *)crc + *crc);
}
-static int check_version(Elf_Shdr *sechdrs,
- unsigned int versindex,
+static int check_version(const struct load_info *info,
const char *symname,
struct module *mod,
const s32 *crc)
{
+ Elf_Shdr *sechdrs = info->sechdrs;
+ unsigned int versindex = info->index.vers;
unsigned int i, num_versions;
struct modversion_info *versions;
@@ -1312,17 +1314,16 @@ static int check_version(Elf_Shdr *sechdrs,
}
/* Broken toolchain. Warn once, then let it go.. */
- pr_warn_once("%s: no symbol version for %s\n", mod->name, symname);
+ pr_warn_once("%s: no symbol version for %s\n", info->name, symname);
return 1;
bad_version:
pr_warn("%s: disagrees about version of symbol %s\n",
- mod->name, symname);
+ info->name, symname);
return 0;
}
-static inline int check_modstruct_version(Elf_Shdr *sechdrs,
- unsigned int versindex,
+static inline int check_modstruct_version(const struct load_info *info,
struct module *mod)
{
const s32 *crc;
@@ -1338,8 +1339,8 @@ static inline int check_modstruct_version(Elf_Shdr *sechdrs,
BUG();
}
preempt_enable();
- return check_version(sechdrs, versindex,
- VMLINUX_SYMBOL_STR(module_layout), mod, crc);
+ return check_version(info, VMLINUX_SYMBOL_STR(module_layout),
+ mod, crc);
}
/* First part is kernel version, which we ignore if module has crcs. */
@@ -1353,8 +1354,7 @@ static inline int same_magic(const char *amagic, const char *bmagic,
return strcmp(amagic, bmagic) == 0;
}
#else
-static inline int check_version(Elf_Shdr *sechdrs,
- unsigned int versindex,
+static inline int check_version(const struct load_info *info,
const char *symname,
struct module *mod,
const s32 *crc)
@@ -1362,8 +1362,7 @@ static inline int check_version(Elf_Shdr *sechdrs,
return 1;
}
-static inline int check_modstruct_version(Elf_Shdr *sechdrs,
- unsigned int versindex,
+static inline int check_modstruct_version(const struct load_info *info,
struct module *mod)
{
return 1;
@@ -1399,7 +1398,7 @@ static const struct kernel_symbol *resolve_symbol(struct module *mod,
if (!sym)
goto unlock;
- if (!check_version(info->sechdrs, info->index.vers, name, mod, crc)) {
+ if (!check_version(info, name, mod, crc)) {
sym = ERR_PTR(-EINVAL);
goto getname;
}
@@ -1662,31 +1661,36 @@ static inline void remove_notes_attrs(struct module *mod)
}
#endif /* CONFIG_KALLSYMS */
-static void add_usage_links(struct module *mod)
+static void del_usage_links(struct module *mod)
{
#ifdef CONFIG_MODULE_UNLOAD
struct module_use *use;
- int nowarn;
mutex_lock(&module_mutex);
- list_for_each_entry(use, &mod->target_list, target_list) {
- nowarn = sysfs_create_link(use->target->holders_dir,
- &mod->mkobj.kobj, mod->name);
- }
+ list_for_each_entry(use, &mod->target_list, target_list)
+ sysfs_remove_link(use->target->holders_dir, mod->name);
mutex_unlock(&module_mutex);
#endif
}
-static void del_usage_links(struct module *mod)
+static int add_usage_links(struct module *mod)
{
+ int ret = 0;
#ifdef CONFIG_MODULE_UNLOAD
struct module_use *use;
mutex_lock(&module_mutex);
- list_for_each_entry(use, &mod->target_list, target_list)
- sysfs_remove_link(use->target->holders_dir, mod->name);
+ list_for_each_entry(use, &mod->target_list, target_list) {
+ ret = sysfs_create_link(use->target->holders_dir,
+ &mod->mkobj.kobj, mod->name);
+ if (ret)
+ break;
+ }
mutex_unlock(&module_mutex);
+ if (ret)
+ del_usage_links(mod);
#endif
+ return ret;
}
static int module_add_modinfo_attrs(struct module *mod)
@@ -1797,13 +1801,18 @@ static int mod_sysfs_setup(struct module *mod,
if (err)
goto out_unreg_param;
- add_usage_links(mod);
+ err = add_usage_links(mod);
+ if (err)
+ goto out_unreg_modinfo_attrs;
+
add_sect_attrs(mod, info);
add_notes_attrs(mod, info);
kobject_uevent(&mod->mkobj.kobj, KOBJ_ADD);
return 0;
+out_unreg_modinfo_attrs:
+ module_remove_modinfo_attrs(mod);
out_unreg_param:
module_param_sysfs_remove(mod);
out_unreg_holders:
@@ -2910,9 +2919,15 @@ static int rewrite_section_headers(struct load_info *info, int flags)
info->index.vers = 0; /* Pretend no __versions section! */
else
info->index.vers = find_sec(info, "__versions");
+ info->sechdrs[info->index.vers].sh_flags &= ~(unsigned long)SHF_ALLOC;
+
info->index.info = find_sec(info, ".modinfo");
+ if (!info->index.info)
+ info->name = "(missing .modinfo section)";
+ else
+ info->name = get_modinfo(info, "name");
info->sechdrs[info->index.info].sh_flags &= ~(unsigned long)SHF_ALLOC;
- info->sechdrs[info->index.vers].sh_flags &= ~(unsigned long)SHF_ALLOC;
+
return 0;
}
@@ -2952,21 +2967,29 @@ static struct module *setup_load_info(struct load_info *info, int flags)
info->index.mod = find_sec(info, ".gnu.linkonce.this_module");
if (!info->index.mod) {
- pr_warn("No module found in object\n");
+ pr_warn("%s: No module found in object\n",
+ info->name ?: "(missing .modinfo name field)");
return ERR_PTR(-ENOEXEC);
}
/* This is temporary: point mod into copy of data. */
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;
+
if (info->index.sym == 0) {
- pr_warn("%s: module has no symbols (stripped?)\n", mod->name);
+ pr_warn("%s: module has no symbols (stripped?)\n", info->name);
return ERR_PTR(-ENOEXEC);
}
info->index.pcpu = find_pcpusec(info);
/* Check module struct version now, before we try to use module. */
- if (!check_modstruct_version(info->sechdrs, info->index.vers, mod))
+ if (!check_modstruct_version(info, mod))
return ERR_PTR(-ENOEXEC);
return mod;
@@ -2987,7 +3010,7 @@ static int check_modinfo(struct module *mod, struct load_info *info, int flags)
return err;
} else if (!same_magic(modmagic, vermagic, info->index.vers)) {
pr_err("%s: version magic '%s' should be '%s'\n",
- mod->name, modmagic, vermagic);
+ info->name, modmagic, vermagic);
return -ENOEXEC;
}
@@ -3237,7 +3260,7 @@ int __weak module_frob_arch_sections(Elf_Ehdr *hdr,
/* module_blacklist is a comma-separated list of module names */
static char *module_blacklist;
-static bool blacklisted(char *module_name)
+static bool blacklisted(const char *module_name)
{
const char *p;
size_t len;
@@ -3267,7 +3290,7 @@ static struct module *layout_and_allocate(struct load_info *info, int flags)
if (IS_ERR(mod))
return mod;
- if (blacklisted(mod->name))
+ if (blacklisted(info->name))
return ERR_PTR(-EPERM);
err = check_modinfo(mod, info, flags);

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