Re: [PATCH bpf-next v4 1/3] bpf, arena: fix range_tree_clear inconsistency on kmalloc_nolock failure

[bot+bpf-ci]

> diff --git a/kernel/bpf/range_tree.c b/kernel/bpf/range_tree.c
> index 2f28886f3ff7..15b588377a76 100644
> --- a/kernel/bpf/range_tree.c
> +++ b/kernel/bpf/range_tree.c
> @@ -143,16 +143,22 @@ int range_tree_clear(struct range_tree *rt, u32 start, u32 len)
>  		if (rn->rn_start < start && rn->rn_last > last) {
>  			u32 old_last = rn->rn_last;
>
> +			/*
> +			 * Pre-allocate the right-half node before modifying
> +			 * the tree. If allocation fails we return -ENOMEM
> +			 * without altering the range tree.
> +			 */
> +			new_rn = kmalloc_nolock(sizeof(struct range_node),
> +						__GFP_ACCOUNT, NUMA_NO_NODE);
> +			if (!new_rn)
> +				return -ENOMEM;
> +
>  			/* Overlaps with the entire clearing range */
>  			range_it_remove(rn, rt);
>  			rn->rn_last = start - 1;
>  			range_it_insert(rn, rt);
>
> -			/* Add a range */
> -			new_rn = kmalloc_nolock(sizeof(struct range_node), __GFP_ACCOUNT,
> -						NUMA_NO_NODE);
> -			if (!new_rn)
> -				return -ENOMEM;
> +			/* Add right-half range */
>  			new_rn->rn_start = last + 1;
>  			new_rn->rn_last = old_last;
>  			range_it_insert(new_rn, rt);

This isn't a bug, but would it read better to keep the "Overlaps with
the entire clearing range" comment at the top of the branch, next to
the condition it describes, rather than having it appear in the middle
after the new allocation block?


---
AI reviewed your patch. Please fix the bug or email reply why it's not a bug.
See: https://github.com/kernel-patches/vmtest/blob/master/ci/claude/README.md

CI run summary: https://github.com/kernel-patches/bpf/actions/runs/32736729475