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module: initialize module dynamic debug later 

We should initialize the module dynamic debug datastructures
only after determining that the module is not loaded yet. This
fixes a bug that introduced in 2.6.35-rc2, where when a trying
to load a module twice, we also load it's dynamic printing data
twice which causes all sorts of nasty issues. Also handle
the dynamic debug cleanup later on failure.

Signed-off-by: Yehuda Sadeh <yehuda@hq.newdream.net>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> (removed a #ifdef)
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
hifive-unleashed-5.1
Yehuda Sadeh 2010-07-03 13:07:35 +10:00 committed by Linus Torvalds
parent e3668dd83b
commit ff49d74ad3
3 changed files with 18 additions and 11 deletions
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4
include/linux/dynamic_debug.h
View File

@ -40,7 +40,7 @@ int ddebug_add_module(struct _ddebug *tab, unsigned int n,
const char *modname);
#if defined(CONFIG_DYNAMIC_DEBUG)
extern int ddebug_remove_module(char *mod_name);
extern int ddebug_remove_module(const char *mod_name);
#define __dynamic_dbg_enabled(dd) ({ \
int __ret = 0; \
@ -73,7 +73,7 @@ extern int ddebug_remove_module(char *mod_name);
#else
static inline int ddebug_remove_module(char *mod)
static inline int ddebug_remove_module(const char *mod)
{
return 0;
}

23
kernel/module.c
View File

@ -2062,6 +2062,12 @@ static void dynamic_debug_setup(struct _ddebug *debug, unsigned int num)
#endif
}
static void dynamic_debug_remove(struct _ddebug *debug)
{
if (debug)
ddebug_remove_module(debug->modname);
}
static void *module_alloc_update_bounds(unsigned long size)
{
void *ret = module_alloc(size);
@ -2124,6 +2130,8 @@ static noinline struct module *load_module(void __user *umod,
void *ptr = NULL; /* Stops spurious gcc warning */
unsigned long symoffs, stroffs, *strmap;
void __percpu *percpu;
struct _ddebug *debug = NULL;
unsigned int num_debug = 0;
mm_segment_t old_fs;
@ -2476,15 +2484,9 @@ static noinline struct module *load_module(void __user *umod,
kfree(strmap);
strmap = NULL;
if (!mod->taints) {
struct _ddebug *debug;
unsigned int num_debug;
if (!mod->taints)
debug = section_objs(hdr, sechdrs, secstrings, "__verbose",
sizeof(*debug), &num_debug);
if (debug)
dynamic_debug_setup(debug, num_debug);
}
err = module_finalize(hdr, sechdrs, mod);
if (err < 0)
@ -2526,10 +2528,13 @@ static noinline struct module *load_module(void __user *umod,
goto unlock;
}
if (debug)
dynamic_debug_setup(debug, num_debug);
/* Find duplicate symbols */
err = verify_export_symbols(mod);
if (err < 0)
goto unlock;
goto ddebug;
list_add_rcu(&mod->list, &modules);
mutex_unlock(&module_mutex);
@ -2557,6 +2562,8 @@ static noinline struct module *load_module(void __user *umod,
mutex_lock(&module_mutex);
/* Unlink carefully: kallsyms could be walking list. */
list_del_rcu(&mod->list);
ddebug:
dynamic_debug_remove(debug);
unlock:
mutex_unlock(&module_mutex);
synchronize_sched();

2
lib/dynamic_debug.c
View File

@ -692,7 +692,7 @@ static void ddebug_table_free(struct ddebug_table *dt)
* Called in response to a module being unloaded. Removes
* any ddebug_table's which point at the module.
*/
int ddebug_remove_module(char *mod_name)
int ddebug_remove_module(const char *mod_name)
{
struct ddebug_table *dt, *nextdt;
int ret = -ENOENT;