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Merge git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-for-linus

Browse source 
* git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-for-linus:
  module: fix bne2 "gave up waiting for init of module libcrc32c"
  module: verify_export_symbols under the lock
  module: move find_module check to end
  module: make locking more fine-grained.
  module: Make module sysfs functions private.
  module: move sysfs exposure to end of load_module
  module: fix kdb's illicit use of struct module_use.
  module: Make the 'usage' lists be two-way
This commit is contained in:
Linus Torvalds 2010-06-04 21:09:48 -07:00
commit 90ec781973
3 changed files with 223 additions and 157 deletions
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44
include/linux/module.h
View file

@ -181,6 +181,13 @@ void *__symbol_get(const char *symbol);
void *__symbol_get_gpl(const char *symbol);
#define symbol_get(x) ((typeof(&x))(__symbol_get(MODULE_SYMBOL_PREFIX #x)))
/* modules using other modules: kdb wants to see this. */
struct module_use {
struct list_head source_list;
struct list_head target_list;
struct module *source, *target;
};
#ifndef __GENKSYMS__
#ifdef CONFIG_MODVERSIONS
/* Mark the CRC weak since genksyms apparently decides not to
@ -359,7 +366,9 @@ struct module
#ifdef CONFIG_MODULE_UNLOAD
/* What modules depend on me? */
struct list_head modules_which_use_me;
struct list_head source_list;
/* What modules do I depend on? */
struct list_head target_list;
/* Who is waiting for us to be unloaded */
struct task_struct *waiter;
@ -663,43 +672,10 @@ static inline int module_get_iter_tracepoints(struct tracepoint_iter *iter)
#endif /* CONFIG_MODULES */
struct device_driver;
#ifdef CONFIG_SYSFS
struct module;
extern struct kset *module_kset;
extern struct kobj_type module_ktype;
extern int module_sysfs_initialized;
int mod_sysfs_init(struct module *mod);
int mod_sysfs_setup(struct module *mod,
struct kernel_param *kparam,
unsigned int num_params);
int module_add_modinfo_attrs(struct module *mod);
void module_remove_modinfo_attrs(struct module *mod);
#else /* !CONFIG_SYSFS */
static inline int mod_sysfs_init(struct module *mod)
{
return 0;
}
static inline int mod_sysfs_setup(struct module *mod,
struct kernel_param *kparam,
unsigned int num_params)
{
return 0;
}
static inline int module_add_modinfo_attrs(struct module *mod)
{
return 0;
}
static inline void module_remove_modinfo_attrs(struct module *mod)
{ }
#endif /* CONFIG_SYSFS */
#define symbol_request(x) try_then_request_module(symbol_get(x), "symbol:" #x)

12
kernel/debug/kdb/kdb_main.c
View file

@ -1857,12 +1857,6 @@ static int kdb_ef(int argc, const char **argv)
}
#if defined(CONFIG_MODULES)
/* modules using other modules */
struct module_use {
struct list_head list;
struct module *module_which_uses;
};
/*
* kdb_lsmod - This function implements the 'lsmod' command. Lists
* currently loaded kernel modules.
@ -1894,9 +1888,9 @@ static int kdb_lsmod(int argc, const char **argv)
{
struct module_use *use;
kdb_printf(" [ ");
list_for_each_entry(use, &mod->modules_which_use_me,
list)
kdb_printf("%s ", use->module_which_uses->name);
list_for_each_entry(use, &mod->source_list,
source_list)
kdb_printf("%s ", use->target->name);
kdb_printf("]\n");
}
#endif

324
kernel/module.c
View file

@ -72,7 +72,11 @@
/* If this is set, the section belongs in the init part of the module */
#define INIT_OFFSET_MASK (1UL << (BITS_PER_LONG-1))
/* List of modules, protected by module_mutex or preempt_disable
/*
* Mutex protects:
* 1) List of modules (also safely readable with preempt_disable),
* 2) module_use links,
* 3) module_addr_min/module_addr_max.
* (delete uses stop_machine/add uses RCU list operations). */
DEFINE_MUTEX(module_mutex);
EXPORT_SYMBOL_GPL(module_mutex);
@ -90,7 +94,8 @@ static DECLARE_WAIT_QUEUE_HEAD(module_wq);
static BLOCKING_NOTIFIER_HEAD(module_notify_list);
/* Bounds of module allocation, for speeding __module_address */
/* Bounds of module allocation, for speeding __module_address.
* Protected by module_mutex. */
static unsigned long module_addr_min = -1UL, module_addr_max = 0;
int register_module_notifier(struct notifier_block * nb)
@ -329,7 +334,7 @@ static bool find_symbol_in_section(const struct symsearch *syms,
}
/* Find a symbol and return it, along with, (optional) crc and
* (optional) module which owns it */
* (optional) module which owns it. Needs preempt disabled or module_mutex. */
const struct kernel_symbol *find_symbol(const char *name,
struct module **owner,
const unsigned long **crc,
@ -523,7 +528,8 @@ static void module_unload_init(struct module *mod)
{
int cpu;
INIT_LIST_HEAD(&mod->modules_which_use_me);
INIT_LIST_HEAD(&mod->source_list);
INIT_LIST_HEAD(&mod->target_list);
for_each_possible_cpu(cpu) {
per_cpu_ptr(mod->refptr, cpu)->incs = 0;
per_cpu_ptr(mod->refptr, cpu)->decs = 0;
@ -535,20 +541,13 @@ static void module_unload_init(struct module *mod)
mod->waiter = current;
}
/* modules using other modules */
struct module_use
{
struct list_head list;
struct module *module_which_uses;
};
/* Does a already use b? */
static int already_uses(struct module *a, struct module *b)
{
struct module_use *use;
list_for_each_entry(use, &b->modules_which_use_me, list) {
if (use->module_which_uses == a) {
list_for_each_entry(use, &b->source_list, source_list) {
if (use->source == a) {
DEBUGP("%s uses %s!\n", a->name, b->name);
return 1;
}
@ -557,62 +556,68 @@ static int already_uses(struct module *a, struct module *b)
return 0;
}
/* Module a uses b */
int use_module(struct module *a, struct module *b)
/*
* Module a uses b
* - we add 'a' as a "source", 'b' as a "target" of module use
* - the module_use is added to the list of 'b' sources (so
* 'b' can walk the list to see who sourced them), and of 'a'
* targets (so 'a' can see what modules it targets).
*/
static int add_module_usage(struct module *a, struct module *b)
{
struct module_use *use;
int no_warn, err;
if (b == NULL || already_uses(a, b)) return 1;
/* If we're interrupted or time out, we fail. */
if (wait_event_interruptible_timeout(
module_wq, (err = strong_try_module_get(b)) != -EBUSY,
30 * HZ) <= 0) {
printk("%s: gave up waiting for init of module %s.\n",
a->name, b->name);
return 0;
}
/* If strong_try_module_get() returned a different error, we fail. */
if (err)
return 0;
DEBUGP("Allocating new usage for %s.\n", a->name);
use = kmalloc(sizeof(*use), GFP_ATOMIC);
if (!use) {
printk("%s: out of memory loading\n", a->name);
module_put(b);
return 0;
printk(KERN_WARNING "%s: out of memory loading\n", a->name);
return -ENOMEM;
}
use->module_which_uses = a;
list_add(&use->list, &b->modules_which_use_me);
no_warn = sysfs_create_link(b->holders_dir, &a->mkobj.kobj, a->name);
return 1;
use->source = a;
use->target = b;
list_add(&use->source_list, &b->source_list);
list_add(&use->target_list, &a->target_list);
return 0;
}
EXPORT_SYMBOL_GPL(use_module);
/* Module a uses b: caller needs module_mutex() */
int ref_module(struct module *a, struct module *b)
{
int err;
if (b == NULL || already_uses(a, b))
return 0;
/* If module isn't available, we fail. */
err = strong_try_module_get(b);
if (err)
return err;
err = add_module_usage(a, b);
if (err) {
module_put(b);
return err;
}
return 0;
}
EXPORT_SYMBOL_GPL(ref_module);
/* Clear the unload stuff of the module. */
static void module_unload_free(struct module *mod)
{
struct module *i;
struct module_use *use, *tmp;
list_for_each_entry(i, &modules, list) {
struct module_use *use;
list_for_each_entry(use, &i->modules_which_use_me, list) {
if (use->module_which_uses == mod) {
DEBUGP("%s unusing %s\n", mod->name, i->name);
module_put(i);
list_del(&use->list);
kfree(use);
sysfs_remove_link(i->holders_dir, mod->name);
/* There can be at most one match. */
break;
}
}
mutex_lock(&module_mutex);
list_for_each_entry_safe(use, tmp, &mod->target_list, target_list) {
struct module *i = use->target;
DEBUGP("%s unusing %s\n", mod->name, i->name);
module_put(i);
list_del(&use->source_list);
list_del(&use->target_list);
kfree(use);
}
mutex_unlock(&module_mutex);
}
#ifdef CONFIG_MODULE_FORCE_UNLOAD
@ -735,7 +740,7 @@ SYSCALL_DEFINE2(delete_module, const char __user *, name_user,
goto out;
}
if (!list_empty(&mod->modules_which_use_me)) {
if (!list_empty(&mod->source_list)) {
/* Other modules depend on us: get rid of them first. */
ret = -EWOULDBLOCK;
goto out;
@ -779,13 +784,14 @@ SYSCALL_DEFINE2(delete_module, const char __user *, name_user,
blocking_notifier_call_chain(&module_notify_list,
MODULE_STATE_GOING, mod);
async_synchronize_full();
mutex_lock(&module_mutex);
/* Store the name of the last unloaded module for diagnostic purposes */
strlcpy(last_unloaded_module, mod->name, sizeof(last_unloaded_module));
ddebug_remove_module(mod->name);
free_module(mod);
out:
free_module(mod);
return 0;
out:
mutex_unlock(&module_mutex);
return ret;
}
@ -799,9 +805,9 @@ static inline void print_unload_info(struct seq_file *m, struct module *mod)
/* Always include a trailing , so userspace can differentiate
between this and the old multi-field proc format. */
list_for_each_entry(use, &mod->modules_which_use_me, list) {
list_for_each_entry(use, &mod->source_list, source_list) {
printed_something = 1;
seq_printf(m, "%s,", use->module_which_uses->name);
seq_printf(m, "%s,", use->source->name);
}
if (mod->init != NULL && mod->exit == NULL) {
@ -880,11 +886,11 @@ static inline void module_unload_free(struct module *mod)
{
}
int use_module(struct module *a, struct module *b)
int ref_module(struct module *a, struct module *b)
{
return strong_try_module_get(b) == 0;
return strong_try_module_get(b);
}
EXPORT_SYMBOL_GPL(use_module);
EXPORT_SYMBOL_GPL(ref_module);
static inline void module_unload_init(struct module *mod)
{
@ -1001,6 +1007,8 @@ static inline int check_modstruct_version(Elf_Shdr *sechdrs,
{
const unsigned long *crc;
/* Since this should be found in kernel (which can't be removed),
* no locking is necessary. */
if (!find_symbol(MODULE_SYMBOL_PREFIX "module_layout", NULL,
&crc, true, false))
BUG();
@ -1043,29 +1051,62 @@ static inline int same_magic(const char *amagic, const char *bmagic,
}
#endif /* CONFIG_MODVERSIONS */
/* Resolve a symbol for this module. I.e. if we find one, record usage.
Must be holding module_mutex. */
/* Resolve a symbol for this module. I.e. if we find one, record usage. */
static const struct kernel_symbol *resolve_symbol(Elf_Shdr *sechdrs,
unsigned int versindex,
const char *name,
struct module *mod)
struct module *mod,
char ownername[])
{
struct module *owner;
const struct kernel_symbol *sym;
const unsigned long *crc;
int err;
mutex_lock(&module_mutex);
sym = find_symbol(name, &owner, &crc,
!(mod->taints & (1 << TAINT_PROPRIETARY_MODULE)), true);
/* use_module can fail due to OOM,
or module initialization or unloading */
if (sym) {
if (!check_version(sechdrs, versindex, name, mod, crc, owner)
|| !use_module(mod, owner))
sym = NULL;
if (!sym)
goto unlock;
if (!check_version(sechdrs, versindex, name, mod, crc, owner)) {
sym = ERR_PTR(-EINVAL);
goto getname;
}
err = ref_module(mod, owner);
if (err) {
sym = ERR_PTR(err);
goto getname;
}
getname:
/* We must make copy under the lock if we failed to get ref. */
strncpy(ownername, module_name(owner), MODULE_NAME_LEN);
unlock:
mutex_unlock(&module_mutex);
return sym;
}
static const struct kernel_symbol *resolve_symbol_wait(Elf_Shdr *sechdrs,
unsigned int versindex,
const char *name,
struct module *mod)
{
const struct kernel_symbol *ksym;
char ownername[MODULE_NAME_LEN];
if (wait_event_interruptible_timeout(module_wq,
!IS_ERR(ksym = resolve_symbol(sechdrs, versindex, name,
mod, ownername)) ||
PTR_ERR(ksym) != -EBUSY,
30 * HZ) <= 0) {
printk(KERN_WARNING "%s: gave up waiting for init of module %s.\n",
mod->name, ownername);
}
return ksym;
}
/*
* /sys/module/foo/sections stuff
* J. Corbet <corbet@lwn.net>
@ -1295,7 +1336,34 @@ static inline void remove_notes_attrs(struct module *mod)
#endif
#ifdef CONFIG_SYSFS
int module_add_modinfo_attrs(struct module *mod)
static void add_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);
}
mutex_unlock(&module_mutex);
#endif
}
static void del_usage_links(struct module *mod)
{
#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);
mutex_unlock(&module_mutex);
#endif
}
static int module_add_modinfo_attrs(struct module *mod)
{
struct module_attribute *attr;
struct module_attribute *temp_attr;
@ -1321,7 +1389,7 @@ int module_add_modinfo_attrs(struct module *mod)
return error;
}
void module_remove_modinfo_attrs(struct module *mod)
static void module_remove_modinfo_attrs(struct module *mod)
{
struct module_attribute *attr;
int i;
@ -1337,7 +1405,7 @@ void module_remove_modinfo_attrs(struct module *mod)
kfree(mod->modinfo_attrs);
}
int mod_sysfs_init(struct module *mod)
static int mod_sysfs_init(struct module *mod)
{
int err;
struct kobject *kobj;
@ -1371,12 +1439,16 @@ int mod_sysfs_init(struct module *mod)
return err;
}
int mod_sysfs_setup(struct module *mod,
static int mod_sysfs_setup(struct module *mod,
struct kernel_param *kparam,
unsigned int num_params)
{
int err;
err = mod_sysfs_init(mod);
if (err)
goto out;
mod->holders_dir = kobject_create_and_add("holders", &mod->mkobj.kobj);
if (!mod->holders_dir) {
err = -ENOMEM;
@ -1391,6 +1463,8 @@ int mod_sysfs_setup(struct module *mod,
if (err)
goto out_unreg_param;
add_usage_links(mod);
kobject_uevent(&mod->mkobj.kobj, KOBJ_ADD);
return 0;
@ -1400,6 +1474,7 @@ int mod_sysfs_setup(struct module *mod,
kobject_put(mod->holders_dir);
out_unreg:
kobject_put(&mod->mkobj.kobj);
out:
return err;
}
@ -1410,14 +1485,40 @@ static void mod_sysfs_fini(struct module *mod)
#else /* CONFIG_SYSFS */
static inline int mod_sysfs_init(struct module *mod)
{
return 0;
}
static inline int mod_sysfs_setup(struct module *mod,
struct kernel_param *kparam,
unsigned int num_params)
{
return 0;
}
static inline int module_add_modinfo_attrs(struct module *mod)
{
return 0;
}
static inline void module_remove_modinfo_attrs(struct module *mod)
{
}
static void mod_sysfs_fini(struct module *mod)
{
}
static void del_usage_links(struct module *mod)
{
}
#endif /* CONFIG_SYSFS */
static void mod_kobject_remove(struct module *mod)
{
del_usage_links(mod);
module_remove_modinfo_attrs(mod);
module_param_sysfs_remove(mod);
kobject_put(mod->mkobj.drivers_dir);
@ -1436,13 +1537,15 @@ static int __unlink_module(void *_mod)
return 0;
}
/* Free a module, remove from lists, etc (must hold module_mutex). */
/* Free a module, remove from lists, etc. */
static void free_module(struct module *mod)
{
trace_module_free(mod);
/* Delete from various lists */
mutex_lock(&module_mutex);
stop_machine(__unlink_module, mod, NULL);
mutex_unlock(&module_mutex);
remove_notes_attrs(mod);
remove_sect_attrs(mod);
mod_kobject_remove(mod);
@ -1493,6 +1596,8 @@ EXPORT_SYMBOL_GPL(__symbol_get);
/*
* Ensure that an exported symbol [global namespace] does not already exist
* in the kernel or in some other module's exported symbol table.
*
* You must hold the module_mutex.
*/
static int verify_export_symbols(struct module *mod)
{
@ -1558,21 +1663,23 @@ static int simplify_symbols(Elf_Shdr *sechdrs,
break;
case SHN_UNDEF:
ksym = resolve_symbol(sechdrs, versindex,
strtab + sym[i].st_name, mod);
ksym = resolve_symbol_wait(sechdrs, versindex,
strtab + sym[i].st_name,
mod);
/* Ok if resolved. */
if (ksym) {
if (ksym && !IS_ERR(ksym)) {
sym[i].st_value = ksym->value;
break;
}
/* Ok if weak. */
if (ELF_ST_BIND(sym[i].st_info) == STB_WEAK)
if (!ksym && ELF_ST_BIND(sym[i].st_info) == STB_WEAK)
break;
printk(KERN_WARNING "%s: Unknown symbol %s\n",
mod->name, strtab + sym[i].st_name);
ret = -ENOENT;
printk(KERN_WARNING "%s: Unknown symbol %s (err %li)\n",
mod->name, strtab + sym[i].st_name,
PTR_ERR(ksym));
ret = PTR_ERR(ksym) ?: -ENOENT;
break;
default:
@ -1960,11 +2067,13 @@ static void *module_alloc_update_bounds(unsigned long size)
void *ret = module_alloc(size);
if (ret) {
mutex_lock(&module_mutex);
/* Update module bounds. */
if ((unsigned long)ret < module_addr_min)
module_addr_min = (unsigned long)ret;
if ((unsigned long)ret + size > module_addr_max)
module_addr_max = (unsigned long)ret + size;
mutex_unlock(&module_mutex);
}
return ret;
}
@ -2139,11 +2248,6 @@ static noinline struct module *load_module(void __user *umod,
goto free_mod;
}
if (find_module(mod->name)) {
err = -EEXIST;
goto free_mod;
}
mod->state = MODULE_STATE_COMING;
/* Allow arches to frob section contents and sizes. */
@ -2234,11 +2338,6 @@ static noinline struct module *load_module(void __user *umod,
/* Now we've moved module, initialize linked lists, etc. */
module_unload_init(mod);
/* add kobject, so we can reference it. */
err = mod_sysfs_init(mod);
if (err)
goto free_unload;
/* Set up license info based on the info section */
set_license(mod, get_modinfo(sechdrs, infoindex, "license"));
@ -2363,11 +2462,6 @@ static noinline struct module *load_module(void __user *umod,
goto cleanup;
}
/* Find duplicate symbols */
err = verify_export_symbols(mod);
if (err < 0)
goto cleanup;
/* Set up and sort exception table */
mod->extable = section_objs(hdr, sechdrs, secstrings, "__ex_table",
sizeof(*mod->extable), &mod->num_exentries);
@ -2426,7 +2520,19 @@ static noinline struct module *load_module(void __user *umod,
* function to insert in a way safe to concurrent readers.
* The mutex protects against concurrent writers.
*/
mutex_lock(&module_mutex);
if (find_module(mod->name)) {
err = -EEXIST;
goto unlock;
}
/* Find duplicate symbols */
err = verify_export_symbols(mod);
if (err < 0)
goto unlock;
list_add_rcu(&mod->list, &modules);
mutex_unlock(&module_mutex);
err = parse_args(mod->name, mod->args, mod->kp, mod->num_kp, NULL);
if (err < 0)
@ -2435,6 +2541,7 @@ static noinline struct module *load_module(void __user *umod,
err = mod_sysfs_setup(mod, mod->kp, mod->num_kp);
if (err < 0)
goto unlink;
add_sect_attrs(mod, hdr->e_shnum, secstrings, sechdrs);
add_notes_attrs(mod, hdr->e_shnum, secstrings, sechdrs);
@ -2447,15 +2554,15 @@ static noinline struct module *load_module(void __user *umod,
return mod;
unlink:
mutex_lock(&module_mutex);
/* Unlink carefully: kallsyms could be walking list. */
list_del_rcu(&mod->list);
unlock:
mutex_unlock(&module_mutex);
synchronize_sched();
module_arch_cleanup(mod);
cleanup:
free_modinfo(mod);
kobject_del(&mod->mkobj.kobj);
kobject_put(&mod->mkobj.kobj);
free_unload:
module_unload_free(mod);
#if defined(CONFIG_MODULE_UNLOAD)
free_percpu(mod->refptr);
@ -2502,19 +2609,10 @@ SYSCALL_DEFINE3(init_module, void __user *, umod,
if (!capable(CAP_SYS_MODULE) || modules_disabled)
return -EPERM;
/* Only one module load at a time, please */
if (mutex_lock_interruptible(&module_mutex) != 0)
return -EINTR;
/* Do all the hard work */
mod = load_module(umod, len, uargs);
if (IS_ERR(mod)) {
mutex_unlock(&module_mutex);
if (IS_ERR(mod))
return PTR_ERR(mod);
}
/* Drop lock so they can recurse */
mutex_unlock(&module_mutex);
blocking_notifier_call_chain(&module_notify_list,
MODULE_STATE_COMING, mod);
@ -2531,9 +2629,7 @@ SYSCALL_DEFINE3(init_module, void __user *, umod,
module_put(mod);
blocking_notifier_call_chain(&module_notify_list,
MODULE_STATE_GOING, mod);
mutex_lock(&module_mutex);
free_module(mod);
mutex_unlock(&module_mutex);
wake_up(&module_wq);
return ret;
}