1 files changed, 79 insertions, 58 deletions

diff --git a/kernel/module.c b/kernel/module.c
index 06ec68f08387..d46c7814a00e 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -495,9 +495,9 @@ struct find_symbol_arg {
 	const struct kernel_symbol *sym;
 };
 
-static bool check_symbol(const struct symsearch *syms,
-				 struct module *owner,
-				 unsigned int symnum, void *data)
+static bool check_exported_symbol(const struct symsearch *syms,
+				  struct module *owner,
+				  unsigned int symnum, void *data)
 {
 	struct find_symbol_arg *fsa = data;
 
@@ -555,9 +555,9 @@ static int cmp_name(const void *va, const void *vb)
 	return strcmp(a, kernel_symbol_name(b));
 }
 
-static bool find_symbol_in_section(const struct symsearch *syms,
-				   struct module *owner,
-				   void *data)
+static bool find_exported_symbol_in_section(const struct symsearch *syms,
+					    struct module *owner,
+					    void *data)
 {
 	struct find_symbol_arg *fsa = data;
 	struct kernel_symbol *sym;
@@ -565,13 +565,14 @@ static bool find_symbol_in_section(const struct symsearch *syms,
 	sym = bsearch(fsa->name, syms->start, syms->stop - syms->start,
 			sizeof(struct kernel_symbol), cmp_name);
 
-	if (sym != NULL && check_symbol(syms, owner, sym - syms->start, data))
+	if (sym != NULL && check_exported_symbol(syms, owner,
+						 sym - syms->start, data))
 		return true;
 
 	return false;
 }
 
-/* Find a symbol and return it, along with, (optional) crc and
+/* Find an exported symbol and return it, along with, (optional) crc and
  * (optional) module which owns it.  Needs preempt disabled or module_mutex. */
 const struct kernel_symbol *find_symbol(const char *name,
 					struct module **owner,
@@ -585,7 +586,7 @@ const struct kernel_symbol *find_symbol(const char *name,
 	fsa.gplok = gplok;
 	fsa.warn = warn;
 
-	if (each_symbol_section(find_symbol_in_section, &fsa)) {
+	if (each_symbol_section(find_exported_symbol_in_section, &fsa)) {
 		if (owner)
 			*owner = fsa.owner;
 		if (crc)
@@ -2159,7 +2160,7 @@ static void free_module(struct module *mod)
 	/* Remove this module from bug list, this uses list_del_rcu */
 	module_bug_cleanup(mod);
 	/* Wait for RCU-sched synchronizing before releasing mod->list and buglist. */
-	synchronize_sched();
+	synchronize_rcu();
 	mutex_unlock(&module_mutex);
 
 	/* This may be empty, but that's OK */
@@ -2198,7 +2199,7 @@ EXPORT_SYMBOL_GPL(__symbol_get);
  *
  * You must hold the module_mutex.
  */
-static int verify_export_symbols(struct module *mod)
+static int verify_exported_symbols(struct module *mod)
 {
 	unsigned int i;
 	struct module *owner;
@@ -2519,10 +2520,10 @@ static void free_modinfo(struct module *mod)
 
 #ifdef CONFIG_KALLSYMS
 
-/* lookup symbol in given range of kernel_symbols */
-static const struct kernel_symbol *lookup_symbol(const char *name,
-	const struct kernel_symbol *start,
-	const struct kernel_symbol *stop)
+/* Lookup exported symbol in given range of kernel_symbols */
+static const struct kernel_symbol *lookup_exported_symbol(const char *name,
+							  const struct kernel_symbol *start,
+							  const struct kernel_symbol *stop)
 {
 	return bsearch(name, start, stop - start,
 			sizeof(struct kernel_symbol), cmp_name);
@@ -2533,9 +2534,10 @@ static int is_exported(const char *name, unsigned long value,
 {
 	const struct kernel_symbol *ks;
 	if (!mod)
-		ks = lookup_symbol(name, __start___ksymtab, __stop___ksymtab);
+		ks = lookup_exported_symbol(name, __start___ksymtab, __stop___ksymtab);
 	else
-		ks = lookup_symbol(name, mod->syms, mod->syms + mod->num_syms);
+		ks = lookup_exported_symbol(name, mod->syms, mod->syms + mod->num_syms);
+
 	return ks != NULL && kernel_symbol_value(ks) == value;
 }
 
@@ -2682,7 +2684,7 @@ static void add_kallsyms(struct module *mod, const struct load_info *info)
 
 	/* Set types up while we still have access to sections. */
 	for (i = 0; i < mod->kallsyms->num_symtab; i++)
-		mod->kallsyms->symtab[i].st_info
+		mod->kallsyms->symtab[i].st_size
 			= elf_type(&mod->kallsyms->symtab[i], info);
 
 	/* Now populate the cut down core kallsyms for after init. */
@@ -3512,15 +3514,15 @@ static noinline int do_init_module(struct module *mod)
 	/*
 	 * We want to free module_init, but be aware that kallsyms may be
 	 * walking this with preempt disabled.  In all the failure paths, we
-	 * call synchronize_sched(), but we don't want to slow down the success
+	 * call synchronize_rcu(), but we don't want to slow down the success
 	 * path, so use actual RCU here.
 	 * Note that module_alloc() on most architectures creates W+X page
 	 * mappings which won't be cleaned up until do_free_init() runs.  Any
 	 * code such as mark_rodata_ro() which depends on those mappings to
 	 * be cleaned up needs to sync with the queued work - ie
-	 * rcu_barrier_sched()
+	 * rcu_barrier()
 	 */
-	call_rcu_sched(&freeinit->rcu, do_free_init);
+	call_rcu(&freeinit->rcu, do_free_init);
 	mutex_unlock(&module_mutex);
 	wake_up_all(&module_wq);
 
@@ -3531,7 +3533,7 @@ fail_free_freeinit:
 fail:
 	/* Try to protect us from buggy refcounters. */
 	mod->state = MODULE_STATE_GOING;
-	synchronize_sched();
+	synchronize_rcu();
 	module_put(mod);
 	blocking_notifier_call_chain(&module_notify_list,
 				     MODULE_STATE_GOING, mod);
@@ -3597,7 +3599,7 @@ static int complete_formation(struct module *mod, struct load_info *info)
 	mutex_lock(&module_mutex);
 
 	/* Find duplicate symbols (must be called under lock). */
-	err = verify_export_symbols(mod);
+	err = verify_exported_symbols(mod);
 	if (err < 0)
 		goto out;
 
@@ -3824,7 +3826,7 @@ static int load_module(struct load_info *info, const char __user *uargs,
  ddebug_cleanup:
 	ftrace_release_mod(mod);
 	dynamic_debug_remove(mod, info->debug);
-	synchronize_sched();
+	synchronize_rcu();
 	kfree(mod->args);
  free_arch_cleanup:
 	module_arch_cleanup(mod);
@@ -3839,7 +3841,7 @@ static int load_module(struct load_info *info, const char __user *uargs,
 	mod_tree_remove(mod);
 	wake_up_all(&module_wq);
 	/* Wait for RCU-sched synchronizing before releasing mod->list. */
-	synchronize_sched();
+	synchronize_rcu();
 	mutex_unlock(&module_mutex);
  free_module:
 	/* Free lock-classes; relies on the preceding sync_rcu() */
@@ -3916,18 +3918,22 @@ static inline int is_arm_mapping_symbol(const char *str)
 	       && (str[2] == '\0' || str[2] == '.');
 }
 
-static const char *symname(struct mod_kallsyms *kallsyms, unsigned int symnum)
+static const char *kallsyms_symbol_name(struct mod_kallsyms *kallsyms, unsigned int symnum)
 {
 	return kallsyms->strtab + kallsyms->symtab[symnum].st_name;
 }
 
-static const char *get_ksymbol(struct module *mod,
-			       unsigned long addr,
-			       unsigned long *size,
-			       unsigned long *offset)
+/*
+ * Given a module and address, find the corresponding symbol and return its name
+ * while providing its size and offset if needed.
+ */
+static const char *find_kallsyms_symbol(struct module *mod,
+					unsigned long addr,
+					unsigned long *size,
+					unsigned long *offset)
 {
 	unsigned int i, best = 0;
-	unsigned long nextval;
+	unsigned long nextval, bestval;
 	struct mod_kallsyms *kallsyms = rcu_dereference_sched(mod->kallsyms);
 
 	/* At worse, next value is at end of module */
@@ -3936,34 +3942,40 @@ static const char *get_ksymbol(struct module *mod,
 	else
 		nextval = (unsigned long)mod->core_layout.base+mod->core_layout.text_size;
 
+	bestval = kallsyms_symbol_value(&kallsyms->symtab[best]);
+
 	/* Scan for closest preceding symbol, and next symbol. (ELF
 	   starts real symbols at 1). */
 	for (i = 1; i < kallsyms->num_symtab; i++) {
-		if (kallsyms->symtab[i].st_shndx == SHN_UNDEF)
+		const Elf_Sym *sym = &kallsyms->symtab[i];
+		unsigned long thisval = kallsyms_symbol_value(sym);
+
+		if (sym->st_shndx == SHN_UNDEF)
 			continue;
 
 		/* We ignore unnamed symbols: they're uninformative
 		 * and inserted at a whim. */
-		if (*symname(kallsyms, i) == '\0'
-		    || is_arm_mapping_symbol(symname(kallsyms, i)))
+		if (*kallsyms_symbol_name(kallsyms, i) == '\0'
+		    || is_arm_mapping_symbol(kallsyms_symbol_name(kallsyms, i)))
 			continue;
 
-		if (kallsyms->symtab[i].st_value <= addr
-		    && kallsyms->symtab[i].st_value > kallsyms->symtab[best].st_value)
+		if (thisval <= addr && thisval > bestval) {
 			best = i;
-		if (kallsyms->symtab[i].st_value > addr
-		    && kallsyms->symtab[i].st_value < nextval)
-			nextval = kallsyms->symtab[i].st_value;
+			bestval = thisval;
+		}
+		if (thisval > addr && thisval < nextval)
+			nextval = thisval;
 	}
 
 	if (!best)
 		return NULL;
 
 	if (size)
-		*size = nextval - kallsyms->symtab[best].st_value;
+		*size = nextval - bestval;
 	if (offset)
-		*offset = addr - kallsyms->symtab[best].st_value;
-	return symname(kallsyms, best);
+		*offset = addr - bestval;
+
+	return kallsyms_symbol_name(kallsyms, best);
 }
 
 void * __weak dereference_module_function_descriptor(struct module *mod,
@@ -3988,7 +4000,8 @@ const char *module_address_lookup(unsigned long addr,
 	if (mod) {
 		if (modname)
 			*modname = mod->name;
-		ret = get_ksymbol(mod, addr, size, offset);
+
+		ret = find_kallsyms_symbol(mod, addr, size, offset);
 	}
 	/* Make a copy in here where it's safe */
 	if (ret) {
@@ -4011,9 +4024,10 @@ int lookup_module_symbol_name(unsigned long addr, char *symname)
 		if (within_module(addr, mod)) {
 			const char *sym;
 
-			sym = get_ksymbol(mod, addr, NULL, NULL);
+			sym = find_kallsyms_symbol(mod, addr, NULL, NULL);
 			if (!sym)
 				goto out;
+
 			strlcpy(symname, sym, KSYM_NAME_LEN);
 			preempt_enable();
 			return 0;
@@ -4036,7 +4050,7 @@ int lookup_module_symbol_attrs(unsigned long addr, unsigned long *size,
 		if (within_module(addr, mod)) {
 			const char *sym;
 
-			sym = get_ksymbol(mod, addr, size, offset);
+			sym = find_kallsyms_symbol(mod, addr, size, offset);
 			if (!sym)
 				goto out;
 			if (modname)
@@ -4065,9 +4079,11 @@ int module_get_kallsym(unsigned int symnum, unsigned long *value, char *type,
 			continue;
 		kallsyms = rcu_dereference_sched(mod->kallsyms);
 		if (symnum < kallsyms->num_symtab) {
-			*value = kallsyms->symtab[symnum].st_value;
-			*type = kallsyms->symtab[symnum].st_info;
-			strlcpy(name, symname(kallsyms, symnum), KSYM_NAME_LEN);
+			const Elf_Sym *sym = &kallsyms->symtab[symnum];
+
+			*value = kallsyms_symbol_value(sym);
+			*type = sym->st_size;
+			strlcpy(name, kallsyms_symbol_name(kallsyms, symnum), KSYM_NAME_LEN);
 			strlcpy(module_name, mod->name, MODULE_NAME_LEN);
 			*exported = is_exported(name, *value, mod);
 			preempt_enable();
@@ -4079,15 +4095,19 @@ int module_get_kallsym(unsigned int symnum, unsigned long *value, char *type,
 	return -ERANGE;
 }
 
-static unsigned long mod_find_symname(struct module *mod, const char *name)
+/* Given a module and name of symbol, find and return the symbol's value */
+static unsigned long find_kallsyms_symbol_value(struct module *mod, const char *name)
 {
 	unsigned int i;
 	struct mod_kallsyms *kallsyms = rcu_dereference_sched(mod->kallsyms);
 
-	for (i = 0; i < kallsyms->num_symtab; i++)
-		if (strcmp(name, symname(kallsyms, i)) == 0 &&
-		    kallsyms->symtab[i].st_shndx != SHN_UNDEF)
-			return kallsyms->symtab[i].st_value;
+	for (i = 0; i < kallsyms->num_symtab; i++) {
+		const Elf_Sym *sym = &kallsyms->symtab[i];
+
+		if (strcmp(name, kallsyms_symbol_name(kallsyms, i)) == 0 &&
+		    sym->st_shndx != SHN_UNDEF)
+			return kallsyms_symbol_value(sym);
+	}
 	return 0;
 }
 
@@ -4102,12 +4122,12 @@ unsigned long module_kallsyms_lookup_name(const char *name)
 	preempt_disable();
 	if ((colon = strnchr(name, MODULE_NAME_LEN, ':')) != NULL) {
 		if ((mod = find_module_all(name, colon - name, false)) != NULL)
-			ret = mod_find_symname(mod, colon+1);
+			ret = find_kallsyms_symbol_value(mod, colon+1);
 	} else {
 		list_for_each_entry_rcu(mod, &modules, list) {
 			if (mod->state == MODULE_STATE_UNFORMED)
 				continue;
-			if ((ret = mod_find_symname(mod, name)) != 0)
+			if ((ret = find_kallsyms_symbol_value(mod, name)) != 0)
 				break;
 		}
 	}
@@ -4132,12 +4152,13 @@ int module_kallsyms_on_each_symbol(int (*fn)(void *, const char *,
 		if (mod->state == MODULE_STATE_UNFORMED)
 			continue;
 		for (i = 0; i < kallsyms->num_symtab; i++) {
+			const Elf_Sym *sym = &kallsyms->symtab[i];
 
-			if (kallsyms->symtab[i].st_shndx == SHN_UNDEF)
+			if (sym->st_shndx == SHN_UNDEF)
 				continue;
 
-			ret = fn(data, symname(kallsyms, i),
-				 mod, kallsyms->symtab[i].st_value);
+			ret = fn(data, kallsyms_symbol_name(kallsyms, i),
+				 mod, kallsyms_symbol_value(sym));
 			if (ret != 0)
 				return ret;
 		}