Re: [bpf PATCH v2 1/3] bpf: tls, implement unhash to avoid transition out of ESTABLISHED

[John Fastabend]

On 4/25/19 12:29 PM, Jakub Kicinski wrote:
> On Thu, 25 Apr 2019 09:03:08 -0700, John Fastabend wrote:
>> +static void tls_sk_proto_unhash(struct sock *sk)
>> +{
>> +    struct tls_context *ctx = tls_get_ctx(sk);
>> +    void (*sk_proto_unhash)(struct sock *sk);
>> +    bool free_ctx;
>> +
>> +    if (!ctx)
>> +            return sk->sk_prot->unhash(sk);
>> +    sk_proto_unhash = ctx->sk_proto_unhash;
>> +    free_ctx = tls_sk_proto_destroy(sk, ctx, false);
>> +    tls_put_ctx(sk);
> 
> Oh, I think you can't put_ctx() unconditionally,
> when free_ctx is false, tls_device_sk_destruct() 
> needs it the ctx pointer.
> 
> I think this explains the offload crashing.
> 

ugh yeah. So we need to _not_ free it from tls_sk_proto_destroy
do the put_ctx and then finally free it. Otherwise we can't
restore the sk_proto fields. v3 on its way. Thanks.

>> +    if (sk_proto_unhash)
>> +            sk_proto_unhash(sk);
>> +    if (free_ctx)
>> +            tls_ctx_free(ctx);
>> +}
>>  
>> -skip_tx_cleanup:
>> +static void tls_sk_proto_close(struct sock *sk, long timeout)
>> +{
>> +    void (*sk_proto_close)(struct sock *sk, long timeout);
>> +    struct tls_context *ctx = tls_get_ctx(sk);
>> +    bool free_ctx;
>> +
>> +    if (!ctx)
>> +            return sk->sk_prot->destroy(sk);
>> +
>> +    lock_sock(sk);
>> +    sk_proto_close = ctx->sk_proto_close;
>> +    free_ctx = tls_sk_proto_destroy(sk, ctx, true);
>> +    tls_put_ctx(sk);