erofs: fix double free of 'copied'

Dan reported a new smatch warning [1]
"fs/erofs/inode.c:210 erofs_read_inode() error: double free of 'copied'"

Due to new chunk-based format handling logic, the error path can be
called after kfree(copied).

Set "copied = NULL" after kfree(copied) to fix this.

[1] https://lore.kernel.org/r/202108251030.bELQozR7-lkp@intel.com

Link: https://lore.kernel.org/r/20210825120757.11034-1-hsiangkao@linux.alibaba.com
Fixes: c5aa903a59db ("erofs: support reading chunk-based uncompressed files")
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>

diff --git a/fs/erofs/inode.c b/fs/erofs/inode.c
index 4408929..31ac3a7 100644 (file)
--- a/fs/erofs/inode.c
+++ b/fs/erofs/inode.c
@@ -127,6 +127,7 @@ static struct page *erofs_read_inode(struct inode *inode,
                        /* fill chunked inode summary info */
                        vi->chunkformat = le16_to_cpu(die->i_u.c.format);
                kfree(copied);
+               copied = NULL;
                break;
        case EROFS_INODE_LAYOUT_COMPACT:
                vi->inode_isize = sizeof(struct erofs_inode_compact);