Re: [PATCH] hfsplus: don't use BUG_ON() in hfsplus_create_attributes_file()

[Viacheslav Dubeyko]

On Wed, 2025-06-25 at 19:10 +0900, Tetsuo Handa wrote:
> syzkaller can mount crafted filesystem images.
> Don't crash the kernel when we can continue.
> 
> Reported-by: syzbot <syzbot+1107451c16b9eb9d29e6@xxxxxxxxxxxxxxxxxxxxxxxxx>
> Closes: https://syzkaller.appspot.com/bug?extid=1107451c16b9eb9d29e6  
> Signed-off-by: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx>
> ---
>  fs/hfsplus/xattr.c | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/fs/hfsplus/xattr.c b/fs/hfsplus/xattr.c
> index 9a1a93e3888b..191767d4cf78 100644
> --- a/fs/hfsplus/xattr.c
> +++ b/fs/hfsplus/xattr.c
> @@ -172,7 +172,11 @@ static int hfsplus_create_attributes_file(struct super_block *sb)
>  		return PTR_ERR(attr_file);
>  	}
>  
> -	BUG_ON(i_size_read(attr_file) != 0);

So, it's something like unexpected situation here. Why do we have
i_size_read(attr_file) != 0 here? It looks like hfsplus_create_attributes_file()
was called in incorrect context. Probably, it's not the whole fix. Any ideas?

> +	if (i_size_read(attr_file) != 0) {
> +		err = -EIO;
> +		pr_err("failed to load attributes file\n");
> +		goto end_attr_file_creation;
> +	}
>  
>  	hip = HFSPLUS_I(attr_file);
>  

Makes sense to me. Looks good.

Reviewed-by: Viacheslav Dubeyko <slava@xxxxxxxxxxx>

Thanks,
Slava.