[PATCH bpf-next v5 1/5] bpf: Move JIT for single-subprog programs to verifier

[Xu Kuohai]

On 3/4/2026 2:05 PM, Eduard Zingerman wrote:
> On Mon, 2026-03-02 at 18:27 +0800, Xu Kuohai wrote:
> 
> [...]
> 
>> diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
>> index fc4ccd1de569..ab2bc0850770 100644
>> --- a/kernel/bpf/verifier.c
>> +++ b/kernel/bpf/verifier.c
>> @@ -26086,6 +26086,11 @@ int bpf_check(struct bpf_prog **prog, union bpf_attr *attr, bpfptr_t uattr, __u3
>>   		convert_pseudo_ld_imm64(env);
>>   	}
>>   
>> +	/* constants blinding in the JIT may increase prog->len */
>> +	len = env->prog->len;
>> +	if (env->subprog_cnt == 1)
>> +		env->prog = bpf_prog_select_jit(env->prog, &ret);
>> +
> 
> I probably miss something important, but would it be possible to put a
> call to __bpf_prog_select_runtime() here and remove it from syscall.c:bpf_prog_load()?
> Thus avoiding the need for `jit_attempted` parameter.
>

Makes sense. In fact, at first I planned to move the whole thing to verifier,
but since this series is just fixing a JIT issue, I ultimately decided to only
move the JIT code to avoid unnecessary changes.

> [...]