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Subject[PATCH v4] kernel/module: Fix mem leak in module_add_modinfo_attrs
Date
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 <yuehaibing@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

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