[PATCH bpf-next v4 1/4] bpf: Fix an off-by-one error in check_indirect_jump

[Xu Kuohai]

On 1/14/2026 6:29 PM, Anton Protopopov wrote:
> On 26/01/14 05:39PM, Xu Kuohai wrote:
>> From: Xu Kuohai <xukuohai at huawei.com>
>>
>> Fix an off-by-one error in check_indirect_jump() that skips the last
>> element returned by copy_insn_array_uniq().
>>
>> Fixes: 493d9e0d6083 ("bpf, x86: add support for indirect jumps")
>> Signed-off-by: Xu Kuohai <xukuohai at huawei.com>
>> ---
>>   kernel/bpf/verifier.c | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
>> index faa1ecc1fe9d..22605d9e0ffa 100644
>> --- a/kernel/bpf/verifier.c
>> +++ b/kernel/bpf/verifier.c
>> @@ -20336,7 +20336,7 @@ static int check_indirect_jump(struct bpf_verifier_env *env, struct bpf_insn *in
>>   		return -EINVAL;
>>   	}
>>   
>> -	for (i = 0; i < n - 1; i++) {
>> +	for (i = 0; i < n; i++) {
>>   		other_branch = push_stack(env, env->gotox_tmp_buf->items[i],
>>   					  env->insn_idx, env->cur_state->speculative);
>>   		if (IS_ERR(other_branch))
>> -- 
>> 2.47.3
> 
> Nack, the last state doesn't require a push_stack() call, it is
> verified directly under this loop. Instead of this patch, just
> add another call to mark_indirect_target().

Ok, I see. Thanks for the explanation.