Re: [PATCH net] tls: skip empty data records in tls_sw_splice_read()

[Qingfang Deng]

On 2026/9/30 13:29, netdev-bot+sinfo@xxxxxxxxxx wrote:
> Hi!
>
> This is an automated message. This series looks like a fix, but its
> commit messages seem to be missing some information:
>
>   - Whether the issue was actually triggered, or is only theoretical
>     (e.g. found by code inspection). If it was triggered please include
>     the symptoms, like the stack trace or error messages.
>
> Please do not repost the series just to address the above. Instead,
> reply to this email with the missing information, so that reviewers
> can take it into account. If the series needs another revision for
> other reasons, please include the information in the commit messages
> then.
>
> The evaluation is done by an LLM so it may be wrong, if you think
> that is the case please reply and explain.

Quoting Sashiko's reply:

> When an application invokes splice() on a TLS 1.3 socket and a 
> 0-length record arrives, rxm->full_len is 0, making chunk 0. 
> net/tls/tls_sw.c:tls_sw_splice_read() { ... chunk = min_t(unsigned 
> int, rxm->full_len, len); copied = skb_splice_bits(skb, sk, 
> rxm->offset, pipe, chunk, flags); if (copied < 0) goto splice_requeue; 
> if (copied < rxm->full_len) { rxm->offset += copied; rxm->full_len -= 
> copied; goto splice_requeue; } consume_skb(skb); splice_read_end: 
> tls_rx_reader_unlock(sk, ctx); return copied ? : err; } Because copied 
> is 0, the copied < rxm->full_len check fails, the SKB is consumed, and 
> the function returns 0. Returning 0 from a splice operation signals 
> End-of-File to userspace, which would erroneously drop the live 
> connection.

Best regards,