Messages in this thread | ![/](/images/icornerl.gif) | | Date | Thu, 9 Dec 2021 16:39:37 +0800 | Subject | Re: [PATCH] btrfs: Fix memory leak in __add_inode_ref() | From | Qu Wenruo <> |
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On 2021/12/9 14:56, 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>
Reviewed-by: Qu Wenruo <wqu@suse.com>
BTW, mind to share the way how you exposed the missing kfree()?
Some awesome static analyse tool or just by eyeballing?
Thanks, Qu > --- > fs/btrfs/tree-log.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c > index 8ab33caf016f..d373fec55521 100644 > --- a/fs/btrfs/tree-log.c > +++ b/fs/btrfs/tree-log.c > @@ -1181,6 +1181,7 @@ static inline int __add_inode_ref(struct btrfs_trans_handle *trans, > parent_objectid, victim_name, > victim_name_len); > if (ret < 0) { > + kfree(victim_name); > return ret; > } else if (!ret) { > ret = -ENOENT; >
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