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Subject[PATCH] Remove mod_bound macro and unify kernel_text_address().
Date
Linus, please apply.

Various archs (i386, m68k, s390, s390x, m68k, parisc, um, x86_64)
implement kernel_text_address. Put this in kernel/extable.c, and the
module iteration inside module.c.

Other than cleanliness, this finally allows the module list and lock
to be static to kernel/module.c (you didn't think I actually cared
about those archs did you?)

It also drops the module->init_size to zero when it's discarded, so
bounds checking is simplified (and the /proc/modules size statistic
will be more accurate, too).

Cheers!
Rusty.
--
Anyone who quotes me in their sig is an idiot. -- Rusty Russell.

Name: module_bound removal patch
Author: Rusty Russell
Status: Tested on 2.5.54
Depends: Module/extable.patch.gz

D: This removes the mod_bound macro, and its usage in determining
D: whether an address is in the kernel (on some archs). It is
D: replaced with a general kernel_text_address() function, and finally
D: makes the modules list static to module.c.

diff -urNp --exclude TAGS -X /home/rusty/current-dontdiff --minimal working-2.5-bk-test/arch/i386/kernel/traps.c working-2.5-bk-module-bound-removal/arch/i386/kernel/traps.c
--- working-2.5-bk-test/arch/i386/kernel/traps.c Mon Jan 6 16:39:20 2003
+++ working-2.5-bk-module-bound-removal/arch/i386/kernel/traps.c Mon Jan 6 16:56:32 2003
@@ -87,50 +87,6 @@ asmlinkage void machine_check(void);

static int kstack_depth_to_print = 24;

-
-/*
- * If the address is either in the .text section of the
- * kernel, or in the vmalloc'ed module regions, it *may*
- * be the address of a calling routine
- */
-
-#ifdef CONFIG_MODULES
-
-/* FIXME: Accessed without a lock --RR */
-extern struct list_head modules;
-
-static inline int kernel_text_address(unsigned long addr)
-{
- int retval = 0;
- struct module *mod;
-
- if (addr >= (unsigned long) &_stext &&
- addr <= (unsigned long) &_etext)
- return 1;
-
- list_for_each_entry(mod, &modules, list) {
- /* mod_bound tests for addr being inside the vmalloc'ed
- * module area. Of course it'd be better to test only
- * for the .text subset... */
- if (mod_bound((void *)addr, 0, mod)) {
- retval = 1;
- break;
- }
- }
-
- return retval;
-}
-
-#else
-
-static inline int kernel_text_address(unsigned long addr)
-{
- return (addr >= (unsigned long) &_stext &&
- addr <= (unsigned long) &_etext);
-}
-
-#endif
-
void show_trace(unsigned long * stack)
{
int i;
diff -urNp --exclude TAGS -X /home/rusty/current-dontdiff --minimal working-2.5-bk-test/arch/m68k/kernel/traps.c working-2.5-bk-module-bound-removal/arch/m68k/kernel/traps.c
--- working-2.5-bk-test/arch/m68k/kernel/traps.c Thu Jan 2 14:47:57 2003
+++ working-2.5-bk-module-bound-removal/arch/m68k/kernel/traps.c Mon Jan 6 16:56:32 2003
@@ -821,42 +821,6 @@ asmlinkage void buserr_c(struct frame *f

static int kstack_depth_to_print = 48;

-extern char _stext, _etext;
-
-#ifdef CONFIG_MODULES
-
-/* FIXME: Accessed without a lock --RR */
-extern struct list_head modules;
-
-static inline int kernel_text_address(unsigned long addr)
-{
- struct module *mod;
-
- if (addr >= (unsigned long) &_stext &&
- addr <= (unsigned long) &_etext)
- return 1;
-
- list_for_each_entry(mod, &modules, list) {
- /* mod_bound tests for addr being inside the vmalloc'ed
- * module area. Of course it'd be better to test only
- * for the .text subset... */
- if (mod_bound((void *)addr, 0, mod))
- return 1;
- }
-
- return 0;
-}
-
-#else // !CONFIG_MODULES
-
-static inline int kernel_text_address(unsigned long addr)
-{
- return (addr >= (unsigned long) &_stext &&
- addr <= (unsigned long) &_etext);
-}
-
-#endif // !CONFIG_MODULES
-
void show_trace(unsigned long *stack)
{
unsigned long *endstack;
diff -urNp --exclude TAGS -X /home/rusty/current-dontdiff --minimal working-2.5-bk-test/arch/parisc/kernel/traps.c working-2.5-bk-module-bound-removal/arch/parisc/kernel/traps.c
--- working-2.5-bk-test/arch/parisc/kernel/traps.c Thu Jan 2 12:32:35 2003
+++ working-2.5-bk-module-bound-removal/arch/parisc/kernel/traps.c Mon Jan 6 16:58:50 2003
@@ -123,31 +123,6 @@ void dump_stack(void)


static int kstack_depth_to_print = 48;
-extern struct module kernel_module;
-
-static inline int kernel_text_address(unsigned long addr)
-{
-#ifdef CONFIG_MODULES
- struct module *mod;
-#endif
- extern char _stext, _etext;
-
- if (addr >= (unsigned long) &_stext &&
- addr <= (unsigned long) &_etext)
- return 1;
-
-#ifdef CONFIG_MODULES
- for (mod = module_list; mod != &kernel_module; mod = mod->next) {
- /* mod_bound tests for addr being inside the vmalloc'ed
- * module area. Of course it'd be better to test only
- * for the .text subset... */
- if (mod_bound(addr, 0, mod))
- return 1;
- }
-#endif
-
- return 0;
-}

void show_stack(unsigned long *sp)
{
diff -urNp --exclude TAGS -X /home/rusty/current-dontdiff --minimal working-2.5-bk-test/arch/s390/kernel/traps.c working-2.5-bk-module-bound-removal/arch/s390/kernel/traps.c
--- working-2.5-bk-test/arch/s390/kernel/traps.c Thu Jan 2 12:35:59 2003
+++ working-2.5-bk-module-bound-removal/arch/s390/kernel/traps.c Mon Jan 6 16:56:32 2003
@@ -63,50 +63,6 @@ static ext_int_info_t ext_int_pfault;

static int kstack_depth_to_print = 12;

-/*
- * If the address is either in the .text section of the
- * kernel, or in the vmalloc'ed module regions, it *may*
- * be the address of a calling routine
- */
-extern char _stext, _etext;
-
-#ifdef CONFIG_MODULES
-
-/* FIXME: Accessed without a lock --RR */
-extern struct list_head modules;
-
-static inline int kernel_text_address(unsigned long addr)
-{
- int retval = 0;
- struct module *mod;
-
- if (addr >= (unsigned long) &_stext &&
- addr <= (unsigned long) &_etext)
- return 1;
-
- list_for_each_entry(mod, &modules, list) {
- /* mod_bound tests for addr being inside the vmalloc'ed
- * module area. Of course it'd be better to test only
- * for the .text subset... */
- if (mod_bound((void*)addr, 0, mod)) {
- retval = 1;
- break;
- }
- }
-
- return retval;
-}
-
-#else
-
-static inline int kernel_text_address(unsigned long addr)
-{
- return (addr >= (unsigned long) &_stext &&
- addr <= (unsigned long) &_etext);
-}
-
-#endif
-
void show_trace(unsigned long * stack)
{
unsigned long backchain, low_addr, high_addr, ret_addr;
diff -urNp --exclude TAGS -X /home/rusty/current-dontdiff --minimal working-2.5-bk-test/arch/s390x/kernel/traps.c working-2.5-bk-module-bound-removal/arch/s390x/kernel/traps.c
--- working-2.5-bk-test/arch/s390x/kernel/traps.c Thu Jan 2 12:35:59 2003
+++ working-2.5-bk-module-bound-removal/arch/s390x/kernel/traps.c Mon Jan 6 16:56:32 2003
@@ -65,50 +65,6 @@ static ext_int_info_t ext_int_pfault;

static int kstack_depth_to_print = 20;

-/*
- * If the address is either in the .text section of the
- * kernel, or in the vmalloc'ed module regions, it *may*
- * be the address of a calling routine
- */
-extern char _stext, _etext;
-
-#ifdef CONFIG_MODULES
-
-/* FIXME: Accessed without a lock --RR */
-extern struct list_head modules;
-
-static inline int kernel_text_address(unsigned long addr)
-{
- int retval = 0;
- struct module *mod;
-
- if (addr >= (unsigned long) &_stext &&
- addr <= (unsigned long) &_etext)
- return 1;
-
- list_for_each_entry(mod, &modules, list) {
- /* mod_bound tests for addr being inside the vmalloc'ed
- * module area. Of course it'd be better to test only
- * for the .text subset... */
- if (mod_bound((void*)addr, 0, mod)) {
- retval = 1;
- break;
- }
- }
-
- return retval;
-}
-
-#else
-
-static inline int kernel_text_address(unsigned long addr)
-{
- return (addr >= (unsigned long) &_stext &&
- addr <= (unsigned long) &_etext);
-}
-
-#endif
-
void show_trace(unsigned long * stack)
{
unsigned long backchain, low_addr, high_addr, ret_addr;
diff -urNp --exclude TAGS -X /home/rusty/current-dontdiff --minimal working-2.5-bk-test/arch/um/kernel/sysrq.c working-2.5-bk-module-bound-removal/arch/um/kernel/sysrq.c
--- working-2.5-bk-test/arch/um/kernel/sysrq.c Thu Jan 2 14:47:58 2003
+++ working-2.5-bk-module-bound-removal/arch/um/kernel/sysrq.c Mon Jan 6 16:56:32 2003
@@ -11,49 +11,6 @@
#include "sysrq.h"
#include "user_util.h"

- /*
- * If the address is either in the .text section of the
- * kernel, or in the vmalloc'ed module regions, it *may*
- * be the address of a calling routine
- */
-
-#ifdef CONFIG_MODULES
-
-/* FIXME: Accessed without a lock --RR */
-extern struct list_head modules;
-
-static inline int kernel_text_address(unsigned long addr)
-{
- int retval = 0;
- struct module *mod;
-
- if (addr >= (unsigned long) &_stext &&
- addr <= (unsigned long) &_etext)
- return 1;
-
- list_for_each_entry(mod, &modules, list) {
- /* mod_bound tests for addr being inside the vmalloc'ed
- * module area. Of course it'd be better to test only
- * for the .text subset... */
- if (mod_bound((void *) addr, 0, mod)) {
- retval = 1;
- break;
- }
- }
-
- return retval;
-}
-
-#else
-
-static inline int kernel_text_address(unsigned long addr)
-{
- return (addr >= (unsigned long) &_stext &&
- addr <= (unsigned long) &_etext);
-}
-
-#endif
-
void show_trace(unsigned long * stack)
{
int i;
diff -urNp --exclude TAGS -X /home/rusty/current-dontdiff --minimal working-2.5-bk-test/arch/x86_64/kernel/traps.c working-2.5-bk-module-bound-removal/arch/x86_64/kernel/traps.c
--- working-2.5-bk-test/arch/x86_64/kernel/traps.c Mon Jan 6 16:39:24 2003
+++ working-2.5-bk-module-bound-removal/arch/x86_64/kernel/traps.c Mon Jan 6 16:56:32 2003
@@ -104,44 +104,6 @@ int printk_address(unsigned long address
}
#endif

-
-#ifdef CONFIG_MODULES
-
-/* FIXME: Accessed without a lock --RR */
-extern struct list_head modules;
-
-static inline int kernel_text_address(unsigned long addr)
-{
- int retval = 0;
- struct module *mod;
-
- if (addr >= (unsigned long) &_stext &&
- addr <= (unsigned long) &_etext)
- return 1;
-
- list_for_each_entry(mod, &modules, list) {
- /* mod_bound tests for addr being inside the vmalloc'ed
- * module area. Of course it'd be better to test only
- * for the .text subset... */
- if (mod_bound((void *)addr, 0, mod)) {
- retval = 1;
- break;
- }
- }
-
- return retval;
-}
-
-#else
-
-static inline int kernel_text_address(unsigned long addr)
-{
- return (addr >= (unsigned long) &_stext &&
- addr <= (unsigned long) &_etext);
-}
-
-#endif
-
static inline unsigned long *in_exception_stack(int cpu, unsigned long stack)
{
int k;
diff -urNp --exclude TAGS -X /home/rusty/current-dontdiff --minimal working-2.5-bk-test/include/linux/kernel.h working-2.5-bk-module-bound-removal/include/linux/kernel.h
--- working-2.5-bk-test/include/linux/kernel.h Mon Jan 6 16:39:32 2003
+++ working-2.5-bk-module-bound-removal/include/linux/kernel.h Mon Jan 6 16:56:32 2003
@@ -84,6 +84,7 @@ extern unsigned long long memparse(char
extern void dev_probe_lock(void);
extern void dev_probe_unlock(void);

+extern int kernel_text_address(unsigned long addr);
extern int session_of_pgrp(int pgrp);

asmlinkage int printk(const char * fmt, ...)
diff -urNp --exclude TAGS -X /home/rusty/current-dontdiff --minimal working-2.5-bk-test/include/linux/module.h working-2.5-bk-module-bound-removal/include/linux/module.h
--- working-2.5-bk-test/include/linux/module.h Mon Jan 6 16:39:32 2003
+++ working-2.5-bk-module-bound-removal/include/linux/module.h Mon Jan 6 16:56:32 2003
@@ -234,6 +234,9 @@ static inline int module_is_live(struct
return mod->state != MODULE_STATE_GOING;
}

+/* Is this address in a module? */
+int module_text_address(unsigned long addr);
+
#ifdef CONFIG_MODULE_UNLOAD

void __symbol_put(const char *symbol);
@@ -324,6 +327,12 @@ search_module_extables(unsigned long add
return NULL;
}

+/* Is this address in a module? */
+static int module_text_address(unsigned long addr)
+{
+ return 0;
+}
+
/* Get/put a kernel symbol (calls should be symmetric) */
#define symbol_get(x) (&(x))
#define symbol_put(x) do { } while(0)
@@ -420,14 +429,6 @@ extern int module_dummy_usage;
#define GET_USE_COUNT(module) (module_dummy_usage)
#define MOD_IN_USE 0
#define __MODULE_STRING(x) __stringify(x)
-#define __mod_between(a_start, a_len, b_start, b_len) \
-(((a_start) >= (b_start) && (a_start) <= (b_start)+(b_len)) \
- || ((a_start)+(a_len) >= (b_start) \
- && (a_start)+(a_len) <= (b_start)+(b_len)))
-#define mod_bound(p, n, m) \
-(((m)->module_init \
- && __mod_between((p),(n),(m)->module_init,(m)->init_size)) \
- || __mod_between((p),(n),(m)->module_core,(m)->core_size))

/*
* The exception and symbol tables, and the lock
diff -urNp --exclude TAGS -X /home/rusty/current-dontdiff --minimal working-2.5-bk-test/kernel/extable.c working-2.5-bk-module-bound-removal/kernel/extable.c
--- working-2.5-bk-test/kernel/extable.c Mon Jan 6 16:39:33 2003
+++ working-2.5-bk-module-bound-removal/kernel/extable.c Mon Jan 6 16:56:32 2003
@@ -19,6 +19,7 @@

extern const struct exception_table_entry __start___ex_table[];
extern const struct exception_table_entry __stop___ex_table[];
+extern char _stext[], _etext[];

/* Given an address, look for it in the exception tables. */
const struct exception_table_entry *search_exception_tables(unsigned long addr)
@@ -29,4 +30,13 @@ const struct exception_table_entry *sear
if (!e)
e = search_module_extables(addr);
return e;
+}
+
+int kernel_text_address(unsigned long addr)
+{
+ if (addr >= (unsigned long)_stext &&
+ addr <= (unsigned long)_etext)
+ return 1;
+
+ return module_text_address(addr);
}
diff -urNp --exclude TAGS -X /home/rusty/current-dontdiff --minimal working-2.5-bk-test/kernel/module.c working-2.5-bk-module-bound-removal/kernel/module.c
--- working-2.5-bk-test/kernel/module.c Mon Jan 6 21:04:48 2003
+++ working-2.5-bk-module-bound-removal/kernel/module.c Mon Jan 6 17:42:54 2003
@@ -54,9 +54,9 @@
/* Protects extables and symbols lists */
static spinlock_t modlist_lock = SPIN_LOCK_UNLOCKED;

-/* List of modules, protected by module_mutex */
+/* List of modules, protected by module_mutex AND modlist_lock */
static DECLARE_MUTEX(module_mutex);
-LIST_HEAD(modules); /* FIXME: Accessed w/o lock on oops by some archs */
+static LIST_HEAD(modules);
static LIST_HEAD(symbols);
static LIST_HEAD(extables);

@@ -754,8 +754,8 @@ unsigned long find_symbol_internal(Elf_S
static void free_module(struct module *mod)
{
/* Delete from various lists */
- list_del(&mod->list);
spin_lock_irq(&modlist_lock);
+ list_del(&mod->list);
list_del(&mod->symbols.list);
list_del(&mod->gpl_symbols.list);
list_del(&mod->extable.list);
@@ -1290,7 +1293,7 @@ sys_init_module(void *umod,
list_add(&mod->extable.list, &extables);
list_add_tail(&mod->symbols.list, &symbols);
list_add_tail(&mod->gpl_symbols.list, &symbols);
- spin_unlock_irq(&modlist_lock);
list_add(&mod->list, &modules);
+ spin_unlock_irq(&modlist_lock);

/* Drop lock so they can recurse */
up(&module_mutex);
@@ -1321,28 +1321,17 @@ sys_init_module(void *umod,
mod->state = MODULE_STATE_LIVE;
module_free(mod, mod->module_init);
mod->module_init = NULL;
+ mod->init_size = 0;

return 0;
}

-#ifdef CONFIG_KALLSYMS
-static inline int inside_init(struct module *mod, unsigned long addr)
-{
- if (mod->module_init
- && (unsigned long)mod->module_init <= addr
- && (unsigned long)mod->module_init + mod->init_size > addr)
- return 1;
- return 0;
-}
-
-static inline int inside_core(struct module *mod, unsigned long addr)
+static inline int within(unsigned long addr, void *start, unsigned long size)
{
- if ((unsigned long)mod->module_core <= addr
- && (unsigned long)mod->module_core + mod->core_size > addr)
- return 1;
- return 0;
+ return ((void *)addr >= start && (void *)addr < start + size);
}

+#ifdef CONFIG_KALLSYMS
static const char *get_ksymbol(struct module *mod,
unsigned long addr,
unsigned long *size,
@@ -1352,7 +1341,7 @@ static const char *get_ksymbol(struct mo
unsigned long nextval;

/* At worse, next value is at end of module */
- if (inside_core(mod, addr))
+ if (within(addr, mod->module_init, mod->init_size))
nextval = (unsigned long)mod->module_core+mod->core_size;
else
nextval = (unsigned long)mod->module_init+mod->init_size;
@@ -1390,7 +1379,8 @@ const char *module_address_lookup(unsign
struct module *mod;

list_for_each_entry(mod, &modules, list) {
- if (inside_core(mod, addr) || inside_init(mod, addr)) {
+ if (within(addr, mod->module_init, mod->init_size)
+ || within(addr, mod->module_core, mod->core_size)) {
*modname = mod->name;
return get_ksymbol(mod, addr, size, offset);
}
@@ -1472,6 +1462,18 @@ const struct exception_table_entry *sear
/* Now, if we found one, we are running inside it now, hence
we cannot unload the module, hence no refcnt needed. */
return e;
+}
+
+/* Is this a valid kernel address? We don't grab the lock: we are oopsing. */
+int module_text_address(unsigned long addr)
+{
+ struct module *mod;
+
+ list_for_each_entry(mod, &modules, list)
+ if (within(addr, mod->module_init, mod->init_size)
+ || within(addr, mod->module_core, mod->core_size))
+ return 1;
+ return 0;
}

/* Provided by the linker */
-
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