Re: [PATCH 1/2] bcachefs: Using vmalloc_array() for array space allocation

On Aug 11, 2025, at 20:09, Liao Yuanhong <[email protected]> wrote:
> 
> Replace kmalloc(size * sizeof) with kmalloc_array() for safer memory
> allocation and overflow prevention.
> 
> Signed-off-by: Liao Yuanhong <[email protected]>
> ---
> fs/bcachefs/btree_key_cache.c    | 2 +-
> fs/bcachefs/btree_trans_commit.c | 2 +-
> 2 files changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/fs/bcachefs/btree_key_cache.c b/fs/bcachefs/btree_key_cache.c
> index 4890cbc88e7c..8dd70024e513 100644
> --- a/fs/bcachefs/btree_key_cache.c
> +++ b/fs/bcachefs/btree_key_cache.c
> @@ -136,7 +136,7 @@ static struct bkey_cached *__bkey_cached_alloc(unsigned key_u64s, gfp_t gfp)
> struct bkey_cached *ck = kmem_cache_zalloc(bch2_key_cache, gfp);
> if (unlikely(!ck))
> return NULL;
> - ck->k = kmalloc(key_u64s * sizeof(u64), gfp);
> + ck->k = kmalloc_array(key_u64s, sizeof(u64), gfp);
> if (unlikely(!ck->k)) {
> kmem_cache_free(bch2_key_cache, ck);
> return NULL;
> diff --git a/fs/bcachefs/btree_trans_commit.c b/fs/bcachefs/btree_trans_commit.c
> index 4d58bdb233e9..4102a3cb2410 100644
> --- a/fs/bcachefs/btree_trans_commit.c
> +++ b/fs/bcachefs/btree_trans_commit.c
> @@ -396,7 +396,7 @@ btree_key_can_insert_cached_slowpath(struct btree_trans *trans, unsigned flags,
> bch2_trans_unlock_updates_write(trans);
> bch2_trans_unlock(trans);
> 
> - new_k = kmalloc(new_u64s * sizeof(u64), GFP_KERNEL);
> + new_k = kmalloc_array(new_u64s, sizeof(u64), GFP_KERNEL);

No, it’s not an array.

> if (!new_k) {
> struct bch_fs *c = trans->c;
> bch_err(c, "error allocating memory for key cache key, btree %s u64s %u",
> -- 
> 2.34.1
> 
>