Re: [PATCH bpf] bpf, sockmap: Fix bug that strp_done cannot be called

[Xu Kuohai <xukuohai@huaweicloud.com>]

On 8/1/2023 11:55 AM, John Fastabend wrote:
> Xu Kuohai wrote:
>> From: Xu Kuohai <xukuohai@huawei.com>
>>
>> strp_done is only called when psock->progs.stream_parser is not NULL,
>> but stream_parser was set to NULL by sk_psock_stop_strp(), called
>> by sk_psock_drop() earlier. So, strp_done can never be called.
>>
>> Introduce SK_PSOCK_RX_ENABLED to mark whether there is strp on psock.
>> Change the condition for calling strp_done from judging whether
>> stream_parser is set to judging whether this flag is set. This flag is
>> only set once when strp_init() succeeds, and will never be cleared later.
>>
>> Fixes: c0d95d3380ee ("bpf, sockmap: Re-evaluate proto ops when psock is removed from sockmap")
>> Signed-off-by: Xu Kuohai <xukuohai@huawei.com>
>> ---
>>   include/linux/skmsg.h |  1 +
>>   net/core/skmsg.c      | 10 ++++++++--
>>   2 files changed, 9 insertions(+), 2 deletions(-)
>>
>> diff --git a/include/linux/skmsg.h b/include/linux/skmsg.h
>> index 054d7911bfc9..959c5f4c4d19 100644
>> --- a/include/linux/skmsg.h
>> +++ b/include/linux/skmsg.h
>> @@ -62,6 +62,7 @@ struct sk_psock_progs {
>>   
>>   enum sk_psock_state_bits {
>>   	SK_PSOCK_TX_ENABLED,
>> +	SK_PSOCK_RX_ENABLED,
> 
> small nit can be make this SK_PSOCK_RX_STRP_ENABLED? That way its
> explicit what we are talking about here.
>

OK, I'll rename it, thanks.

> Otherwise it looks good thanks nice catch.
> 
>>   };
>>   
>>   struct sk_psock_link {
>> diff --git a/net/core/skmsg.c b/net/core/skmsg.c
>> index a29508e1ff35..7c2764beeb04 100644
>> --- a/net/core/skmsg.c
>> +++ b/net/core/skmsg.c
>> @@ -1120,13 +1120,19 @@ static void sk_psock_strp_data_ready(struct sock *sk)
>>   
>>   int sk_psock_init_strp(struct sock *sk, struct sk_psock *psock)
>>   {
>> +	int ret;
>> +
>>   	static const struct strp_callbacks cb = {
>>   		.rcv_msg	= sk_psock_strp_read,
>>   		.read_sock_done	= sk_psock_strp_read_done,
>>   		.parse_msg	= sk_psock_strp_parse,
>>   	};
>>   
>> -	return strp_init(&psock->strp, sk, &cb);
>> +	ret = strp_init(&psock->strp, sk, &cb);
>> +	if (!ret)
>> +		sk_psock_set_state(psock, SK_PSOCK_RX_ENABLED);
>> +
>> +	return ret;
>>   }
>>   
>>   void sk_psock_start_strp(struct sock *sk, struct sk_psock *psock)
>> @@ -1154,7 +1160,7 @@ void sk_psock_stop_strp(struct sock *sk, struct sk_psock *psock)
>>   static void sk_psock_done_strp(struct sk_psock *psock)
>>   {
>>   	/* Parser has been stopped */
>> -	if (psock->progs.stream_parser)
>> +	if (sk_psock_test_state(psock, SK_PSOCK_RX_ENABLED))
>>   		strp_done(&psock->strp);
>>   }
>>   #else
>> -- 
>> 2.30.2
>>