Re: [PATCH v3] hfs: remove BUG() from hfs_release_folio()/hfs_test_inode()/hfs_write_inode()

[Viacheslav Dubeyko]

On Fri, 2025-07-18 at 00:32 +0900, Tetsuo Handa wrote:
> Since syzkaller can mount crafted filesystem images with inode->i_ino == 0
> (which is not listed as "Some special File ID numbers" in fs/hfs/hfs.h ),
> replace BUG() with pr_err().
> 
> Reported-by: syzbot+97e301b4b82ae803d21b@xxxxxxxxxxxxxxxxxxxxxxxxx
> Closes: https://syzkaller.appspot.com/bug?extid=97e301b4b82ae803d21b  
> Signed-off-by: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx>
> ---
>  fs/hfs/inode.c | 8 +++++---
>  1 file changed, 5 insertions(+), 3 deletions(-)
> 
> diff --git a/fs/hfs/inode.c b/fs/hfs/inode.c
> index a81ce7a740b9..9bbf2883bb8f 100644
> --- a/fs/hfs/inode.c
> +++ b/fs/hfs/inode.c
> @@ -81,7 +81,8 @@ static bool hfs_release_folio(struct folio *folio, gfp_t mask)
>  		tree = HFS_SB(sb)->cat_tree;
>  		break;
>  	default:
> -		BUG();
> +		pr_err("detected unknown inode %lu, running fsck.hfs is recommended.\n",
> +		       inode->i_ino);
>  		return false;
>  	}
>  
> @@ -305,7 +306,7 @@ static int hfs_test_inode(struct inode *inode, void *data)
>  	case HFS_CDR_FIL:
>  		return inode->i_ino == be32_to_cpu(rec->file.FlNum);
>  	default:
> -		BUG();
> +		pr_err("detected unknown type %u, running fsck.hfs is recommended.\n", rec->type);
>  		return 1;
>  	}
>  }
> @@ -441,7 +442,8 @@ int hfs_write_inode(struct inode *inode, struct writeback_control *wbc)
>  			hfs_btree_write(HFS_SB(inode->i_sb)->cat_tree);
>  			return 0;
>  		default:
> -			BUG();
> +			pr_err("detected unknown inode %lu, running fsck.hfs is recommended.\n",
> +			       inode->i_ino);
>  			return -EIO;
>  		}
>  	}

Looks good!

Reviewed-by: Viacheslav Dubeyko <slava@xxxxxxxxxxx>

Thanks,
Slava.