[PATCH v1] erofs-utils: fix memory leaks and allocation issue

[Gao Xiang]

Hi Yuezhang,

On 2025/9/9 10:52, Yuezhang Mo wrote:
> This patch addresses 4 memory leaks and 1 allocation issue to
> ensure proper cleanup and allocation:
> 
> 1. Fixed memory leak by freeing sbi->zmgr in z_erofs_compress_exit().
> 2. Fixed memory leak by freeing inode->chunkindexes in erofs_iput().
> 3. Fixed incorrect allocation of chunk index array in
>     erofs_rebuild_write_blob_index() to ensure correct array allocation
>     and avoid out-of-bounds access.
> 4. Fixed memory leak of struct erofs_blobchunk not being freed by
>     calling erofs_blob_exit() in rebuild mode.
> 5. Fix memory leak by calling erofs_put_super().
>     In main(), erofs_read_superblock() is called only to get the block
>     size. In erofs_mkfs_rebuild_load_trees(), erofs_read_superblock()
>     is called again, causing sbi->devs to be overwritten without being
>     released.
> 
> Signed-off-by: Yuezhang Mo <Yuezhang.Mo at sony.com>
> Reviewed-by: Friendy Su <friendy.su at sony.com>
> Reviewed-by: Daniel Palmer <daniel.palmer at sony.com>

Thanks for your patch and sorry for a bit delay...

> ---
>   lib/compress.c | 2 ++
>   lib/inode.c    | 3 +++
>   lib/rebuild.c  | 2 +-
>   mkfs/main.c    | 3 ++-
>   4 files changed, 8 insertions(+), 2 deletions(-)
> 
> diff --git a/lib/compress.c b/lib/compress.c
> index 622a205..dd537ec 100644
> --- a/lib/compress.c
> +++ b/lib/compress.c
> @@ -2171,5 +2171,7 @@ int z_erofs_compress_exit(struct erofs_sb_info *sbi)
>   		}
>   #endif
>   	}
> +
> +	free(sbi->zmgr);
>   	return 0;
>   }
> diff --git a/lib/inode.c b/lib/inode.c
> index 7ee6b3d..0882875 100644
> --- a/lib/inode.c
> +++ b/lib/inode.c
> @@ -159,6 +159,9 @@ unsigned int erofs_iput(struct erofs_inode *inode)
>   	} else {
>   		free(inode->i_link);
>   	}
> +
> +	if (inode->chunkindexes)
> +		free(inode->chunkindexes);

For now, this needs a check

	if (inode->datalayout == EROFS_INODE_CHUNK_BASED)
		free(inode->chunkindexes);

I admit it's not very clean, but otherwise it doesn't work
since `chunkindexes` is in a union.

>   	free(inode);
>   	return 0;
>   }
> diff --git a/lib/rebuild.c b/lib/rebuild.c
> index 0358567..18e5204 100644
> --- a/lib/rebuild.c
> +++ b/lib/rebuild.c
> @@ -186,7 +186,7 @@ static int erofs_rebuild_write_blob_index(struct erofs_sb_info *dst_sb,
>   
>   	unit = sizeof(struct erofs_inode_chunk_index);
>   	inode->extent_isize = count * unit;
> -	idx = malloc(max(sizeof(*idx), sizeof(void *)));
> +	idx = calloc(count, max(sizeof(*idx), sizeof(void *)));
>   	if (!idx)
>   		return -ENOMEM;
>   	inode->chunkindexes = idx;
> diff --git a/mkfs/main.c b/mkfs/main.c
> index 28588db..bcde787 100644
> --- a/mkfs/main.c
> +++ b/mkfs/main.c
> @@ -1702,6 +1702,7 @@ int main(int argc, char **argv)
>   			goto exit;
>   		}
>   		mkfs_blkszbits = src->blkszbits;
> +		erofs_put_super(src);

Do you really need to fix this now (considering `mkfs.erofs`
will exit finally)?

In priciple, I think it should be fixed with a reference and
something similiar to the kernel fill_super.

I'm not sure if you have more time to improve this anyway,
but the current usage is not perfect on my side...


Thanks,
Gao Xiang

>   	}
>   
>   	if (!incremental_mode)
> @@ -1908,7 +1909,7 @@ exit:
>   	erofs_dev_close(&g_sbi);
>   	erofs_cleanup_compress_hints();
>   	erofs_cleanup_exclude_rules();
> -	if (cfg.c_chunkbits)
> +	if (cfg.c_chunkbits || source_mode == EROFS_MKFS_SOURCE_REBUILD)
>   		erofs_blob_exit();
>   	erofs_xattr_cleanup_name_prefixes();
>   	erofs_rebuild_cleanup();