Re: [PATCH bpf 3/3] bpf: Unconditionally take socket references in lookup helpers

On Thu Jul 30, 2026 at 1:55 PM CEST, Michal Luczaj wrote:
> On 7/29/26 22:32, Emil Tsalapatis wrote:
>> On Thu Jul 23, 2026 at 7:33 AM EDT, Michal Luczaj wrote:
>>> Lookup helpers gate whether to acquire a socket reference on
>>> sk_is_refcounted(), a check re-evaluated at release. An established socket
>>> refcounted at acquire time can gain SOCK_RCU_FREE via
>>> connect(AF_UNSPEC)+listen() before release runs; the release-side re-check
>>> then reads sk_is_refcounted() == false and skips the put. The reference
>>> leaks.
>>>
>>> Make acquire and release unconditional and symmetric: always take a
>>> reference, always put it. Adapt sk_select_reuseport().
>>
>> Reviewed-by: Emil Tsalapatis <[email protected]>
>
> Thanks!
>
>> The bot's concern about the comment style is obviously invalid here.
>
> Are the prompts incorrect?
> https://github.com/masoncl/review-prompts/blob/59469708305eca305cbd9eb94e5aa0ee3627529c/kernel/subsystem/bpf.md#bpf-comment-style
>

The prompt is correct, but we don't bother for existing comments, if you add a
new one, you can use the new style.

Overall, looks like the set is pretty close. You can respin targeting bpf-next
as John suggested (and we can wait for his ack before landing) so it can go
through CI again.

pw-bot: cr

> Michal