[PATCH] ramfs: fix double freeing s_fs_info on failed mount

Wu Fengguang
2009-04-07T06:17:23Z

From: Ingo Molnar <mingo@elte.hu>

If ramfs mount fails, s_fs_info will be freed twice in ramfs_fill_super()
and ramfs_kill_sb(), leading to kernel oops.

Consolidate and beautify the code.
Make sure s_fs_info and s_root are in known good states.

Acked-by: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
fs/ramfs/inode.c | 19 +++++++++++--------
1 file changed, 11 insertions(+), 8 deletions(-)

--- mm.orig/fs/ramfs/inode.c
+++ mm/fs/ramfs/inode.c
@@ -221,22 +221,23 @@ static int ramfs_fill_super(struct super
save_mount_options(sb, data);

fsi = kzalloc(sizeof(struct ramfs_fs_info), GFP_KERNEL);
+ sb->s_fs_info = fsi;
if (!fsi) {
err = -ENOMEM;
goto fail;
}
- sb->s_fs_info = fsi;

err = ramfs_parse_options(data, &fsi->mount_opts);
if (err)
goto fail;

- sb->s_maxbytes = MAX_LFS_FILESIZE;
- sb->s_blocksize = PAGE_CACHE_SIZE;
- sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
- sb->s_magic = RAMFS_MAGIC;
- sb->s_op = &ramfs_ops;
- sb->s_time_gran = 1;
+ sb->s_maxbytes = MAX_LFS_FILESIZE;
+ sb->s_blocksize = PAGE_CACHE_SIZE;
+ sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
+ sb->s_magic = RAMFS_MAGIC;
+ sb->s_op = &ramfs_ops;
+ sb->s_time_gran = 1;
+
inode = ramfs_get_inode(sb, S_IFDIR | fsi->mount_opts.mode, 0);
if (!inode) {
err = -ENOMEM;
@@ -244,14 +245,16 @@ static int ramfs_fill_super(struct super
}

root = d_alloc_root(inode);
+ sb->s_root = root;
if (!root) {
err = -ENOMEM;
goto fail;
}
- sb->s_root = root;
+
return 0;
fail:
kfree(fsi);
+ sb->s_fs_info = NULL;
iput(inode);
return err;
}