Re: [PATCH bpf-next v4 10/20] bpf: Dispatch exception cleanup pads from bpf_throw()

[Yonghong Song <yonghong.song@linux.dev>]

On 9/22/26 2:38 PM, Eduard Zingerman wrote:
> On Mon, 2026-09-21 at 14:01 -0700, Yonghong Song wrote:
>
> ...
>
>> +static int cleanup_pad_body_for_subprog(struct bpf_verifier_env *env, struct bpf_prog *sub,
>> +					u32 start, u32 end)
>> +{
> pad_body{,_bits} are redundant, jits have access to insn_aux_data.
> all this machinery can be dropped.

Good point. This can simplify the code a lot!

>
>> +	unsigned long *bits;
>> +	u32 i, cnt = 0;
>> +
>> +	for (i = start; i < end; i++)
>> +		if (env->insn_aux_data[i].in_cleanup_pad)
>> +			cnt++;
>> +	if (!cnt)
>> +		return 0;
>> +
>> +	bits = bitmap_zalloc(end - start, GFP_KERNEL_ACCOUNT | __GFP_NOWARN);
>> +	if (!bits)
>> +		return -ENOMEM;
>> +
>> +	for (i = start; i < end; i++)
>> +		if (env->insn_aux_data[i].in_cleanup_pad)
>> +			__set_bit(i - start, bits);
>> +
>> +	sub->aux->exc->pad_body = bits;
>> +	sub->aux->exc->pad_body_bits = end - start;
>> +	return 0;
>> +}