[PATCH v4] kernel/module: Fix mem leak in module_add_modinfo_attrs

[YueHaibing]

In module_add_modinfo_attrs if sysfs_create_file
fails, we forget to free allocated modinfo_attrs
and roll back the sysfs files.

Fixes: 03e88ae1b13d ("[PATCH] fix module sysfs files reference counting")
Signed-off-by: YueHaibing <yuehaib...@huawei.com>
---
v4: call module_remove_modinfo_attrs only while i > 0
v3: reuse module_remove_modinfo_attrs
v2: free from '--i' instead of 'i--'
---
 kernel/module.c | 22 +++++++++++++++++-----
 1 file changed, 17 insertions(+), 5 deletions(-)

diff --git a/kernel/module.c b/kernel/module.c
index f954d72..3310a39 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -1696,6 +1696,8 @@ static int add_usage_links(struct module *mod)
        return ret;
 }
 
+static void module_remove_modinfo_attrs(struct module *mod, int end);
+
 static int module_add_modinfo_attrs(struct module *mod)
 {
        struct module_attribute *attr;
@@ -1710,24 +1712,34 @@ static int module_add_modinfo_attrs(struct module *mod)
                return -ENOMEM;
 
        temp_attr = mod->modinfo_attrs;
-       for (i = 0; (attr = modinfo_attrs[i]) && !error; i++) {
+       for (i = 0; (attr = modinfo_attrs[i]); i++) {
                if (!attr->test || attr->test(mod)) {
                        memcpy(temp_attr, attr, sizeof(*temp_attr));
                        sysfs_attr_init(&temp_attr->attr);
                        error = sysfs_create_file(&mod->mkobj.kobj,
                                        &temp_attr->attr);
+                       if (error)
+                               goto error_out;
                        ++temp_attr;
                }
        }
+
+       return 0;
+
+error_out:
+       if (i > 0)
+               module_remove_modinfo_attrs(mod, --i);
        return error;
 }
 
-static void module_remove_modinfo_attrs(struct module *mod)
+static void module_remove_modinfo_attrs(struct module *mod, int end)
 {
        struct module_attribute *attr;
        int i;
 
        for (i = 0; (attr = &mod->modinfo_attrs[i]); i++) {
+               if (end >= 0 && i > end)
+                       break;
                /* pick a field to test for end of list */
                if (!attr->attr.name)
                        break;
@@ -1815,7 +1827,7 @@ static int mod_sysfs_setup(struct module *mod,
        return 0;
 
 out_unreg_modinfo_attrs:
-       module_remove_modinfo_attrs(mod);
+       module_remove_modinfo_attrs(mod, -1);
 out_unreg_param:
        module_param_sysfs_remove(mod);
 out_unreg_holders:
@@ -1851,7 +1863,7 @@ static void mod_sysfs_fini(struct module *mod)
 {
 }
 
-static void module_remove_modinfo_attrs(struct module *mod)
+static void module_remove_modinfo_attrs(struct module *mod, int end)
 {
 }
 
@@ -1867,7 +1879,7 @@ static void init_param_lock(struct module *mod)
 static void mod_sysfs_teardown(struct module *mod)
 {
        del_usage_links(mod);
-       module_remove_modinfo_attrs(mod);
+       module_remove_modinfo_attrs(mod, -1);
        module_param_sysfs_remove(mod);
        kobject_put(mod->mkobj.drivers_dir);
        kobject_put(mod->holders_dir);
-- 
2.7.4