Re: [PATCH net] tcp: fix TFO max_qlen accounting across reuseport migration
From: patchwork-bot+netdevbpf
Date: Wed Aug 05 2026 - 20:20:54 EST
Hello:
This patch was applied to netdev/net.git (main)
by Jakub Kicinski <kuba@xxxxxxxxxx>:
On Mon, 3 Aug 2026 14:17:38 +0800 you wrote:
> A listener's TCP_FASTOPEN max_qlen stops being accurate and lets through
> far more pending Fast Open requests than it was configured for.
>
> This only shows up with SO_REUSEPORT listener migration, where closing a
> listener hands its still-pending TFO children over to a surviving one.
>
> fastopenq.qlen is charged in tcp_fastopen_create_child() when the child
> is created and uncharged in reqsk_fastopen_remove() when the handshake
> completes. The uncharge follows rsk_listener of the request the child
> points at, and inet_reqsk_clone() has repointed the child at a new
> request owned by the new listener, so the ++ and the -- land on two
> different sockets. The new listener's qlen drifts negative and its
> limit no longer binds.
>
> [...]
Here is the summary with links:
- [net] tcp: fix TFO max_qlen accounting across reuseport migration
https://git.kernel.org/netdev/net/c/a0ab2ba83e35
You are awesome, thank you!
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