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Subject[PATCH 87/93] module: add new state MODULE_STATE_UNFORMED.
Date
3.5.7.5 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: Rusty Russell <rusty@rustcorp.com.au>

commit 0d21b0e3477395e7ff2acc269f15df6e6a8d356d upstream.

You should never look at such a module, so it's excised from all paths
which traverse the modules list.

We add the state at the end, to avoid gratuitous ABI break (ksplice).

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Herton Ronaldo Krzesinski <herton.krzesinski@canonical.com>
---
include/linux/module.h | 10 ++++----
kernel/debug/kdb/kdb_main.c | 2 ++
kernel/module.c | 57 +++++++++++++++++++++++++++++++++++++++----
3 files changed, 59 insertions(+), 10 deletions(-)

diff --git a/include/linux/module.h b/include/linux/module.h
index fbcafe2..16100ba 100644
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -196,11 +196,11 @@ struct module_use {
struct module *source, *target;
};

-enum module_state
-{
- MODULE_STATE_LIVE,
- MODULE_STATE_COMING,
- MODULE_STATE_GOING,
+enum module_state {
+ MODULE_STATE_LIVE, /* Normal state. */
+ MODULE_STATE_COMING, /* Full formed, running module_init. */
+ MODULE_STATE_GOING, /* Going away. */
+ MODULE_STATE_UNFORMED, /* Still setting it up. */
};

/**
diff --git a/kernel/debug/kdb/kdb_main.c b/kernel/debug/kdb/kdb_main.c
index 1f91413..8f71ca3 100644
--- a/kernel/debug/kdb/kdb_main.c
+++ b/kernel/debug/kdb/kdb_main.c
@@ -1982,6 +1982,8 @@ static int kdb_lsmod(int argc, const char **argv)

kdb_printf("Module Size modstruct Used by\n");
list_for_each_entry(mod, kdb_modules, list) {
+ if (mod->state == MODULE_STATE_UNFORMED)
+ continue;

kdb_printf("%-20s%8u 0x%p ", mod->name,
mod->core_size, (void *)mod);
diff --git a/kernel/module.c b/kernel/module.c
index 8dd60f4..a2bc837 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -145,6 +145,7 @@ struct load_info {
ongoing or failed initialization etc. */
static inline int strong_try_module_get(struct module *mod)
{
+ BUG_ON(mod && mod->state == MODULE_STATE_UNFORMED);
if (mod && mod->state == MODULE_STATE_COMING)
return -EBUSY;
if (try_module_get(mod))
@@ -300,6 +301,9 @@ bool each_symbol_section(bool (*fn)(const struct symsearch *arr,
#endif
};

+ if (mod->state == MODULE_STATE_UNFORMED)
+ continue;
+
if (each_symbol_in_section(arr, ARRAY_SIZE(arr), mod, fn, data))
return true;
}
@@ -410,16 +414,24 @@ const struct kernel_symbol *find_symbol(const char *name,
EXPORT_SYMBOL_GPL(find_symbol);

/* Search for module by name: must hold module_mutex. */
-struct module *find_module(const char *name)
+static struct module *find_module_all(const char *name,
+ bool even_unformed)
{
struct module *mod;

list_for_each_entry(mod, &modules, list) {
+ if (!even_unformed && mod->state == MODULE_STATE_UNFORMED)
+ continue;
if (strcmp(mod->name, name) == 0)
return mod;
}
return NULL;
}
+
+struct module *find_module(const char *name)
+{
+ return find_module_all(name, false);
+}
EXPORT_SYMBOL_GPL(find_module);

#ifdef CONFIG_SMP
@@ -485,6 +497,8 @@ bool is_module_percpu_address(unsigned long addr)
preempt_disable();

list_for_each_entry_rcu(mod, &modules, list) {
+ if (mod->state == MODULE_STATE_UNFORMED)
+ continue;
if (!mod->percpu_size)
continue;
for_each_possible_cpu(cpu) {
@@ -1008,6 +1022,8 @@ static ssize_t show_initstate(struct module_attribute *mattr,
case MODULE_STATE_GOING:
state = "going";
break;
+ default:
+ BUG();
}
return sprintf(buffer, "%s\n", state);
}
@@ -1746,6 +1762,8 @@ void set_all_modules_text_rw(void)

mutex_lock(&module_mutex);
list_for_each_entry_rcu(mod, &modules, list) {
+ if (mod->state == MODULE_STATE_UNFORMED)
+ continue;
if ((mod->module_core) && (mod->core_text_size)) {
set_page_attributes(mod->module_core,
mod->module_core + mod->core_text_size,
@@ -1767,6 +1785,8 @@ void set_all_modules_text_ro(void)

mutex_lock(&module_mutex);
list_for_each_entry_rcu(mod, &modules, list) {
+ if (mod->state == MODULE_STATE_UNFORMED)
+ continue;
if ((mod->module_core) && (mod->core_text_size)) {
set_page_attributes(mod->module_core,
mod->module_core + mod->core_text_size,
@@ -2878,7 +2898,8 @@ static bool finished_loading(const char *name)

mutex_lock(&module_mutex);
mod = find_module(name);
- ret = !mod || mod->state != MODULE_STATE_COMING;
+ ret = !mod || mod->state == MODULE_STATE_LIVE
+ || mod->state == MODULE_STATE_GOING;
mutex_unlock(&module_mutex);

return ret;
@@ -3197,6 +3218,8 @@ const char *module_address_lookup(unsigned long addr,

preempt_disable();
list_for_each_entry_rcu(mod, &modules, list) {
+ if (mod->state == MODULE_STATE_UNFORMED)
+ continue;
if (within_module_init(addr, mod) ||
within_module_core(addr, mod)) {
if (modname)
@@ -3220,6 +3243,8 @@ int lookup_module_symbol_name(unsigned long addr, char *symname)

preempt_disable();
list_for_each_entry_rcu(mod, &modules, list) {
+ if (mod->state == MODULE_STATE_UNFORMED)
+ continue;
if (within_module_init(addr, mod) ||
within_module_core(addr, mod)) {
const char *sym;
@@ -3244,6 +3269,8 @@ int lookup_module_symbol_attrs(unsigned long addr, unsigned long *size,

preempt_disable();
list_for_each_entry_rcu(mod, &modules, list) {
+ if (mod->state == MODULE_STATE_UNFORMED)
+ continue;
if (within_module_init(addr, mod) ||
within_module_core(addr, mod)) {
const char *sym;
@@ -3271,6 +3298,8 @@ int module_get_kallsym(unsigned int symnum, unsigned long *value, char *type,

preempt_disable();
list_for_each_entry_rcu(mod, &modules, list) {
+ if (mod->state == MODULE_STATE_UNFORMED)
+ continue;
if (symnum < mod->num_symtab) {
*value = mod->symtab[symnum].st_value;
*type = mod->symtab[symnum].st_info;
@@ -3313,9 +3342,12 @@ unsigned long module_kallsyms_lookup_name(const char *name)
ret = mod_find_symname(mod, colon+1);
*colon = ':';
} else {
- list_for_each_entry_rcu(mod, &modules, list)
+ list_for_each_entry_rcu(mod, &modules, list) {
+ if (mod->state == MODULE_STATE_UNFORMED)
+ continue;
if ((ret = mod_find_symname(mod, name)) != 0)
break;
+ }
}
preempt_enable();
return ret;
@@ -3330,6 +3362,8 @@ int module_kallsyms_on_each_symbol(int (*fn)(void *, const char *,
int ret;

list_for_each_entry(mod, &modules, list) {
+ if (mod->state == MODULE_STATE_UNFORMED)
+ continue;
for (i = 0; i < mod->num_symtab; i++) {
ret = fn(data, mod->strtab + mod->symtab[i].st_name,
mod, mod->symtab[i].st_value);
@@ -3345,6 +3379,7 @@ static char *module_flags(struct module *mod, char *buf)
{
int bx = 0;

+ BUG_ON(mod->state == MODULE_STATE_UNFORMED);
if (mod->taints ||
mod->state == MODULE_STATE_GOING ||
mod->state == MODULE_STATE_COMING) {
@@ -3386,6 +3421,10 @@ static int m_show(struct seq_file *m, void *p)
struct module *mod = list_entry(p, struct module, list);
char buf[8];

+ /* We always ignore unformed modules. */
+ if (mod->state == MODULE_STATE_UNFORMED)
+ return 0;
+
seq_printf(m, "%s %u",
mod->name, mod->init_size + mod->core_size);
print_unload_info(m, mod);
@@ -3446,6 +3485,8 @@ const struct exception_table_entry *search_module_extables(unsigned long addr)

preempt_disable();
list_for_each_entry_rcu(mod, &modules, list) {
+ if (mod->state == MODULE_STATE_UNFORMED)
+ continue;
if (mod->num_exentries == 0)
continue;

@@ -3494,10 +3535,13 @@ struct module *__module_address(unsigned long addr)
if (addr < module_addr_min || addr > module_addr_max)
return NULL;

- list_for_each_entry_rcu(mod, &modules, list)
+ list_for_each_entry_rcu(mod, &modules, list) {
+ if (mod->state == MODULE_STATE_UNFORMED)
+ continue;
if (within_module_core(addr, mod)
|| within_module_init(addr, mod))
return mod;
+ }
return NULL;
}
EXPORT_SYMBOL_GPL(__module_address);
@@ -3550,8 +3594,11 @@ void print_modules(void)
printk(KERN_DEFAULT "Modules linked in:");
/* Most callers should already have preempt disabled, but make sure */
preempt_disable();
- list_for_each_entry_rcu(mod, &modules, list)
+ list_for_each_entry_rcu(mod, &modules, list) {
+ if (mod->state == MODULE_STATE_UNFORMED)
+ continue;
printk(" %s%s", mod->name, module_flags(mod, buf));
+ }
preempt_enable();
if (last_unloaded_module[0])
printk(" [last unloaded: %s]", last_unloaded_module);
--
1.7.9.5


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