Re: [PATCH] btrfs: Fix memory leak in __add_inode_ref()

David Sterba
2021-12-09T14:57:41Z

On Thu, Dec 09, 2021 at 02:56:31PM +0800, Jianglei Nie wrote:
> Line 1169 (#3) allocates a memory chunk for victim_name by kmalloc(),
> but when the function returns in line 1184 (#4) victim_name allcoated
> by line 1169 (#3) is not freed, which will lead to a memory leak.
> There is a similar snippet of code in this function as allocating a memory
> chunk for victim_name in line 1104 (#1) as well as releasing the memory
> in line 1116 (#2).
>
> We should kfree() victim_name when the return value of backref_in_log()
> is less than zero and before the function returns in line 1184 (#4).
>
> 1057 static inline int __add_inode_ref(struct btrfs_trans_handle *trans,
> 1058 struct btrfs_root *root,
> 1059 struct btrfs_path *path,
> 1060 struct btrfs_root *log_root,
> 1061 struct btrfs_inode *dir,
> 1062 struct btrfs_inode *inode,
> 1063 u64 inode_objectid, u64 parent_objectid,
> 1064 u64 ref_index, char *name, int namelen,
> 1065 int *search_done)
> 1066 {
>
> 1104 victim_name = kmalloc(victim_name_len, GFP_NOFS);
> // #1: kmalloc (victim_name-1)
> 1105 if (!victim_name)
> 1106 return -ENOMEM;
>
> 1112 ret = backref_in_log(log_root, &search_key,
> 1113 parent_objectid, victim_name,
> 1114 victim_name_len);
> 1115 if (ret < 0) {
> 1116 kfree(victim_name); // #2: kfree (victim_name-1)
> 1117 return ret;
> 1118 } else if (!ret) {
>
> 1169 victim_name = kmalloc(victim_name_len, GFP_NOFS);
> // #3: kmalloc (victim_name-2)
> 1170 if (!victim_name)
> 1171 return -ENOMEM;
>
> 1180 ret = backref_in_log(log_root, &search_key,
> 1181 parent_objectid, victim_name,
> 1182 victim_name_len);
> 1183 if (ret < 0) {
> 1184 return ret; // #4: missing kfree (victim_name-2)
> 1185 } else if (!ret) {
>
> 1241 return 0;
> 1242 }
>
> Signed-off-by: Jianglei Nie <niejianglei2021@163.com>

Added to misc-next, thanks.