Re: Please backport d8616ee2affc ("bpf, sockmap: Fix sk->sk_forward_alloc warn_on in sk_stream_kill_queues") to linux-5.10.y

[Wen Gu <guwen@linux.alibaba.com>]

On 2024/7/2 16:22, Greg KH wrote:
> On Tue, Jul 02, 2024 at 10:07:56AM +0800, Wen Gu wrote:
>>
>>
>> On 2024/6/30 20:55, Wen Gu wrote:
>>> Hi stable team,
>>>
>>> Could you please backport [1] to linux-5.10.y?
>>>
>>> I noticed a regression caused by [2], which was merged to linux-5.10.y since v5.10.80.
>>>
>>> After sock_map_unhash() helper was removed in [2], sock elems added to the bpf sock map
>>> via sock_hash_update_common() cannot be removed if they are in the icsk_accept_queue
>>> of the listener sock. Since they have not been accept()ed, they cannot be removed via
>>> sock_map_close()->sock_map_remove_links() either.
>>>
>>> It can be reproduced in network test with short-lived connections. If the server is
>>> stopped during the test, there is a probability that some sock elems will remain in
>>> the bpf sock map.
>>>
>>> And with [1], the sock_map_destroy() helper is introduced to invoke sock_map_remove_links()
>>> when inet_csk_listen_stop()->inet_child_forget()->inet_csk_destroy_sock(), to remove the
>>> sock elems from the bpf sock map in such situation.
>>>
>>> [1] d8616ee2affc ("bpf, sockmap: Fix sk->sk_forward_alloc warn_on in sk_stream_kill_queues")
>>> (link: https://lore.kernel.org/all/20220524075311.649153-1-wangyufen@huawei.com/)
>>> [2] 8b5c98a67c1b ("bpf, sockmap: Remove unhash handler for BPF sockmap usage")
>>> (link: https://lore.kernel.org/all/20211103204736.248403-3-john.fastabend@gmail.com/)
>>>
>>> Thanks!
>>> Wen Gu
>>
>> Hi stable team,
>>
>> Just want to confirm that the backport of this patch is consistent with the stable tree rules
>> as I thought. And is there any other information I need to provide? :)
> 
> Please relax, you sent this on Sunday and asked about it on Tuesday,
> barely 1 day later?
> 

Sure, there's no intention to rush, just confirming this backport requirement is reasonable. Sorry for the noise.

Thanks.