1 files changed, 23 insertions, 14 deletions

diff --git a/kernel/module.c b/kernel/module.c
index 3202c9950073..c2e3e2e98801 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -81,7 +81,8 @@ int unregister_module_notifier(struct notifier_block * nb)
 }
 EXPORT_SYMBOL(unregister_module_notifier);
 
-/* We require a truly strong try_module_get() */
+/* We require a truly strong try_module_get(): 0 means failure due to
+   ongoing or failed initialization etc. */
 static inline int strong_try_module_get(struct module *mod)
 {
         if (mod && mod->state == MODULE_STATE_COMING)
@@ -952,7 +953,8 @@ static unsigned long resolve_symbol(Elf_Shdr *sechdrs,
         ret = __find_symbol(name, &owner, &crc,
                         !(mod->taints & TAINT_PROPRIETARY_MODULE));
         if (ret) {
-                /* use_module can fail due to OOM, or module unloading */
+                /* use_module can fail due to OOM,
+                   or module initialization or unloading */
                 if (!check_version(sechdrs, versindex, name, mod, crc) ||
                     !use_module(mod, owner))
                         ret = 0;
@@ -1369,7 +1371,7 @@ dup:
         return ret;
 }
 
-/* Change all symbols so that sh_value encodes the pointer directly. */
+/* Change all symbols so that st_value encodes the pointer directly. */
 static int simplify_symbols(Elf_Shdr *sechdrs,
                             unsigned int symindex,
                             const char *strtab,
@@ -2212,29 +2214,34 @@ static const char *get_ksymbol(struct module *mod,
 /* For kallsyms to ask for address resolution.  NULL means not found.
    We don't lock, as this is used for oops resolution and races are a
    lesser concern. */
+/* FIXME: Risky: returns a pointer into a module w/o lock */
 const char *module_address_lookup(unsigned long addr,
                                   unsigned long *size,
                                   unsigned long *offset,
                                   char **modname)
 {
         struct module *mod;
+        const char *ret = NULL;
 
+        preempt_disable();
         list_for_each_entry(mod, &modules, list) {
                 if (within(addr, mod->module_init, mod->init_size)
                     || within(addr, mod->module_core, mod->core_size)) {
                         if (modname)
                                 *modname = mod->name;
-                        return get_ksymbol(mod, addr, size, offset);
+                        ret = get_ksymbol(mod, addr, size, offset);
+                        break;
                 }
         }
-        return NULL;
+        preempt_enable();
+        return ret;
 }
 
 int lookup_module_symbol_name(unsigned long addr, char *symname)
 {
         struct module *mod;
 
-        mutex_lock(&module_mutex);
+        preempt_disable();
         list_for_each_entry(mod, &modules, list) {
                 if (within(addr, mod->module_init, mod->init_size) ||
                     within(addr, mod->module_core, mod->core_size)) {
@@ -2244,12 +2251,12 @@ int lookup_module_symbol_name(unsigned long addr, char *symname)
                         if (!sym)
                                 goto out;
                         strlcpy(symname, sym, KSYM_NAME_LEN);
-                        mutex_unlock(&module_mutex);
+                        preempt_enable();
                         return 0;
                 }
         }
 out:
-        mutex_unlock(&module_mutex);
+        preempt_enable();
         return -ERANGE;
 }
 
@@ -2258,7 +2265,7 @@ int lookup_module_symbol_attrs(unsigned long addr, unsigned long *size,
 {
         struct module *mod;
 
-        mutex_lock(&module_mutex);
+        preempt_disable();
         list_for_each_entry(mod, &modules, list) {
                 if (within(addr, mod->module_init, mod->init_size) ||
                     within(addr, mod->module_core, mod->core_size)) {
@@ -2271,12 +2278,12 @@ int lookup_module_symbol_attrs(unsigned long addr, unsigned long *size,
                                 strlcpy(modname, mod->name, MODULE_NAME_LEN);
                         if (name)
                                 strlcpy(name, sym, KSYM_NAME_LEN);
-                        mutex_unlock(&module_mutex);
+                        preempt_enable();
                         return 0;
                 }
         }
 out:
-        mutex_unlock(&module_mutex);
+        preempt_enable();
         return -ERANGE;
 }
 
@@ -2285,7 +2292,7 @@ int module_get_kallsym(unsigned int symnum, unsigned long *value, char *type,
 {
         struct module *mod;
 
-        mutex_lock(&module_mutex);
+        preempt_disable();
         list_for_each_entry(mod, &modules, list) {
                 if (symnum < mod->num_symtab) {
                         *value = mod->symtab[symnum].st_value;
@@ -2294,12 +2301,12 @@ int module_get_kallsym(unsigned int symnum, unsigned long *value, char *type,
                                 KSYM_NAME_LEN);
                         strlcpy(module_name, mod->name, MODULE_NAME_LEN);
                         *exported = is_exported(name, mod);
-                        mutex_unlock(&module_mutex);
+                        preempt_enable();
                         return 0;
                 }
                 symnum -= mod->num_symtab;
         }
-        mutex_unlock(&module_mutex);
+        preempt_enable();
         return -ERANGE;
 }
 
@@ -2322,6 +2329,7 @@ unsigned long module_kallsyms_lookup_name(const char *name)
         unsigned long ret = 0;
 
         /* Don't lock: we're in enough trouble already. */
+        preempt_disable();
         if ((colon = strchr(name, ':')) != NULL) {
                 *colon = '\0';
                 if ((mod = find_module(name)) != NULL)
@@ -2332,6 +2340,7 @@ unsigned long module_kallsyms_lookup_name(const char *name)
                         if ((ret = mod_find_symname(mod, name)) != 0)
                                 break;
         }
+        preempt_enable();
         return ret;
 }
 #endif /* CONFIG_KALLSYMS */