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>

diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h
index b3cd4de9432b68007342098ad7dbb662cbc1fce0..52c0da4bdd18fe5969fbf9c583652c0f7f00ba07 100644 (file)
--- a/include/linux/dynamic_debug.h
+++ b/include/linux/dynamic_debug.h
@@ -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;
 }

diff --git a/kernel/module.c b/kernel/module.c
index 8c6b42840dd19fa942919aa8e052bf400911a2a4..5d2d28197c827a840d98357c11c1e16b3dce92a2 100644 (file)
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -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();

diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index 3df8eb17a607932bf8091e89c796c338c323c29b..02afc25337284329d23a998e636240d5a41d337d 100644 (file)
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -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;