Re: [PATCH] bcachefs: add check NULL return of bio_kmalloc in journal_read_bucket

[Kent Overstreet]

On Wed, Oct 30, 2024 at 03:48:01PM +0800, Pei Xiao wrote:
> bio_kmalloc may return NULL, will cause NULL pointer dereference.
> Add check NULL return for bio_kmalloc in journal_read_bucket.
> 
> Signed-off-by: Pei Xiao <xiaopei01@xxxxxxxxxx>
> Fixes: ac10a9611d87 ("bcachefs: Some fixes for building in userspace")

Thanks - applied.

> ---
>  fs/bcachefs/errcode.h    | 1 +
>  fs/bcachefs/journal_io.c | 2 ++
>  2 files changed, 3 insertions(+)
> 
> diff --git a/fs/bcachefs/errcode.h b/fs/bcachefs/errcode.h
> index f2736e830007..ae75cb0a842c 100644
> --- a/fs/bcachefs/errcode.h
> +++ b/fs/bcachefs/errcode.h
> @@ -83,6 +83,7 @@
>  	x(ENOMEM,			ENOMEM_fs_other_alloc)			\
>  	x(ENOMEM,			ENOMEM_dev_alloc)			\
>  	x(ENOMEM,			ENOMEM_disk_accounting)			\
> +	x(ENOMEM,                       ENOMEM_journal_read_bucket)             \
>  	x(ENOSPC,			ENOSPC_disk_reservation)		\
>  	x(ENOSPC,			ENOSPC_bucket_alloc)			\
>  	x(ENOSPC,			ENOSPC_disk_label_add)			\
> diff --git a/fs/bcachefs/journal_io.c b/fs/bcachefs/journal_io.c
> index fcb68f111079..667a2bb9e20b 100644
> --- a/fs/bcachefs/journal_io.c
> +++ b/fs/bcachefs/journal_io.c
> @@ -1014,6 +1014,8 @@ static int journal_read_bucket(struct bch_dev *ca,
>  			nr_bvecs = buf_pages(buf->data, sectors_read << 9);
>  
>  			bio = bio_kmalloc(nr_bvecs, GFP_KERNEL);
> +			if (!bio)
> +				return -BCH_ERR_ENOMEM_journal_read_bucket;
>  			bio_init(bio, ca->disk_sb.bdev, bio->bi_inline_vecs, nr_bvecs, REQ_OP_READ);
>  
>  			bio->bi_iter.bi_sector = offset;
> -- 
> 2.34.1
>