Re: [PATCH bpf-next 2/5] bpf: Fix concurrent regression in map_create()

[Leon Hwang]

On 19/5/26 11:05, Alexei Starovoitov wrote:
> On Mon, May 18, 2026 at 7:48 PM Leon Hwang <leon.hwang@xxxxxxxxx> wrote:
>>
>> On 18/5/26 23:40, bot+bpf-ci@xxxxxxxxxx wrote:
[...]
>> diff --git a/include/linux/bpf_verifier.h b/include/linux/bpf_verifier.h
>> index 20c421b43849..a10ef58bb6ea 100644
>> --- a/include/linux/bpf_verifier.h
>> +++ b/include/linux/bpf_verifier.h
>> @@ -788,6 +788,7 @@ struct bpf_log_attr {
>>         u32 level;
>>         u32 offsetof_true_size;
>>         bpfptr_t uattr;
>> +       bool finalized;
>>  };
> 
> No. That looks worse.
> The suggestion was to do the finalize log _once_ before
> allocating FD.

Understand the suggestion.

When tried to finalize log once without "finalized" guard, it seemed
complicated to modify __map_create() to make sure finalize log once on
all code logic paths.

> Why are you doing it twice?

So, to simplify the change, finalize log the second time with the
"finalized" guard to cover all the check-failure paths.

After thinking hardly, the below patch is the way to make sure finalize
log once before security_bpf_map_create().

It works, but it is not good enough.

Thanks,
Leon

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