[PATCH] erofs: add error handling for erofs_fill_super()

[PATCH] erofs: add error handling for erofs_fill_super()

[Chengguang Xu]

There are some potential resource leaks in error case
of erofs_fill_super(), so add proper error handling
for it.

Signed-off-by: Chengguang Xu <cgxu519@mykernel.net>
---
 fs/erofs/super.c | 31 +++++++++++++++++++++++--------
 1 file changed, 23 insertions(+), 8 deletions(-)

diff --git a/fs/erofs/super.c b/fs/erofs/super.c
index 0e369494f2f2..06e721bd1c8c 100644
--- a/fs/erofs/super.c
+++ b/fs/erofs/super.c
@@ -369,7 +369,7 @@ static int erofs_fill_super(struct super_block *sb, void *data, int silent)
 	sb->s_fs_info = sbi;
 	err = erofs_read_superblock(sb);
 	if (err)
-		return err;
+		goto free;
 
 	sb->s_flags |= SB_RDONLY | SB_NOATIME;
 	sb->s_maxbytes = MAX_LFS_FILESIZE;
@@ -385,7 +385,7 @@ static int erofs_fill_super(struct super_block *sb, void *data, int silent)
 
 	err = erofs_parse_options(sb, data);
 	if (err)
-		return err;
+		goto free;
 
 	if (test_opt(sbi, POSIX_ACL))
 		sb->s_flags |= SB_POSIXACL;
@@ -398,29 +398,44 @@ static int erofs_fill_super(struct super_block *sb, void *data, int silent)
 
 	/* get the root inode */
 	inode = erofs_iget(sb, ROOT_NID(sbi), true);
-	if (IS_ERR(inode))
-		return PTR_ERR(inode);
+	if (IS_ERR(inode)) {
+		err = PTR_ERR(inode);
+		goto free;
+	}
 
 	if (!S_ISDIR(inode->i_mode)) {
 		erofs_err(sb, "rootino(nid %llu) is not a directory(i_mode %o)",
 			  ROOT_NID(sbi), inode->i_mode);
 		iput(inode);
-		return -EINVAL;
+		err = -EINVAL;
+		goto free;
 	}
 
 	sb->s_root = d_make_root(inode);
-	if (!sb->s_root)
-		return -ENOMEM;
+	if (!sb->s_root) {
+		err = -ENOMEM;
+		goto free;
+	}
 
 	erofs_shrinker_register(sb);
 	/* sb->s_umount is already locked, SB_ACTIVE and SB_BORN are not set */
 	err = erofs_init_managed_cache(sb);
 	if (err)
-		return err;
+		goto free_root_inode;
 
 	erofs_info(sb, "mounted with opts: %s, root inode @ nid %llu.",
 		   (char *)data, ROOT_NID(sbi));
+
 	return 0;
+
+free_root_inode:
+	dput(sb->s_root);
+	sb->s_root = NULL;
+	erofs_shrinker_unregister(sb);
+free:
+	kfree(sbi);
+	sb->s_fs_info = NULL;
+	return err;
 }
 
 static struct dentry *erofs_mount(struct file_system_type *fs_type, int flags,
-- 
2.20.1

Re: [PATCH] erofs: add error handling for erofs_fill_super()

[Gao Xiang]

Hi Chengguang,

On Tue, Nov 19, 2019 at 07:37:44PM +0800, Chengguang Xu wrote:
> There are some potential resource leaks in error case
> of erofs_fill_super(), so add proper error handling
> for it.
> 
> Signed-off-by: Chengguang Xu <cgxu519@mykernel.net>
> ---
>  fs/erofs/super.c | 31 +++++++++++++++++++++++--------
>  1 file changed, 23 insertions(+), 8 deletions(-)
> 
> diff --git a/fs/erofs/super.c b/fs/erofs/super.c
> index 0e369494f2f2..06e721bd1c8c 100644
> --- a/fs/erofs/super.c
> +++ b/fs/erofs/super.c
> @@ -369,7 +369,7 @@ static int erofs_fill_super(struct super_block *sb, void *data, int silent)
>  	sb->s_fs_info = sbi;
>  	err = erofs_read_superblock(sb);
>  	if (err)
> -		return err;
> +		goto free;

Could you give some hints what is the potential leak exactly?
Actually, it was modified on purpose recently, see the following threads:
https://lore.kernel.org/r/20190720224955.GD17978@ZenIV.linux.org.uk
and
https://lore.kernel.org/r/20190721040547.GF17978@ZenIV.linux.org.uk

Thanks,
Gao Xiang

Re: [PATCH] erofs: add error handling for erofs_fill_super()

[Chengguang Xu]

 ---- 在 星期二, 2019-11-19 20:51:13 Gao Xiang <gaoxiang25@huawei.com> 撰写 ----
 > Hi Chengguang,
 > 
 > On Tue, Nov 19, 2019 at 07:37:44PM +0800, Chengguang Xu wrote:
 > > There are some potential resource leaks in error case
 > > of erofs_fill_super(), so add proper error handling
 > > for it.
 > > 
 > > Signed-off-by: Chengguang Xu <cgxu519@mykernel.net>
 > > ---
 > >  fs/erofs/super.c | 31 +++++++++++++++++++++++--------
 > >  1 file changed, 23 insertions(+), 8 deletions(-)
 > > 
 > > diff --git a/fs/erofs/super.c b/fs/erofs/super.c
 > > index 0e369494f2f2..06e721bd1c8c 100644
 > > --- a/fs/erofs/super.c
 > > +++ b/fs/erofs/super.c
 > > @@ -369,7 +369,7 @@ static int erofs_fill_super(struct super_block *sb, void *data, int silent)
 > >      sb->s_fs_info = sbi;
 > >      err = erofs_read_superblock(sb);
 > >      if (err)
 > > -        return err;
 > > +        goto free;
 > 
 > Could you give some hints what is the potential leak exactly?
 > Actually, it was modified on purpose recently, see the following threads:
 > https://lore.kernel.org/r/20190720224955.GD17978@ZenIV.linux.org.uk
 > and
 > https://lore.kernel.org/r/20190721040547.GF17978@ZenIV.linux.org.uk

Sorry, it seems I misread some part of code, please just drop the patch.

Thanks

Re: [PATCH] erofs: add error handling for erofs_fill_super()

[Chengguang Xu]

 ---- 在 星期二, 2019-11-19 20:51:13 Gao Xiang <gaoxiang25@huawei.com> 撰写 ----
 > Hi Chengguang,
 > 
 > On Tue, Nov 19, 2019 at 07:37:44PM +0800, Chengguang Xu wrote:
 > > There are some potential resource leaks in error case
 > > of erofs_fill_super(), so add proper error handling
 > > for it.
 > > 
 > > Signed-off-by: Chengguang Xu <cgxu519@mykernel.net>
 > > ---
 > >  fs/erofs/super.c | 31 +++++++++++++++++++++++--------
 > >  1 file changed, 23 insertions(+), 8 deletions(-)
 > > 
 > > diff --git a/fs/erofs/super.c b/fs/erofs/super.c
 > > index 0e369494f2f2..06e721bd1c8c 100644
 > > --- a/fs/erofs/super.c
 > > +++ b/fs/erofs/super.c
 > > @@ -369,7 +369,7 @@ static int erofs_fill_super(struct super_block *sb, void *data, int silent)
 > >      sb->s_fs_info = sbi;
 > >      err = erofs_read_superblock(sb);
 > >      if (err)
 > > -        return err;
 > > +        goto free;
 > 
 > Could you give some hints what is the potential leak exactly?
 > Actually, it was modified on purpose recently, see the following threads:
 > https://lore.kernel.org/r/20190720224955.GD17978@ZenIV.linux.org.uk
 > and
 > https://lore.kernel.org/r/20190721040547.GF17978@ZenIV.linux.org.uk

Sorry, it seems I misread some part of code, please just drop the patch.

Thanks