NACK: [SRU][J][PATCH v1 0/1] tcp: fix forever orphan socket caused by tcp_abort

[Thibault Ferrante]

Incorrect threading let's this thread stays opens on some tooling,
putting correct closure.

On 19/06/2025 19:39, Stav Aviram wrote:
>  From d41ec707dbe3fb3fa5b124a31fb9a8fd401fb1b3 Mon Sep 17 00:00:00 2001
> Message-Id: <cover.1750244904.git.saviram at nvidia.com>
> From: Stav Aviram <saviram at nvidia.com>
> Date: Wed, 18 Jun 2025 14:08:24 +0300
> To: kernel-team at lists.ubuntu.com
> Subject: [SRU][J][PATCH v1 0/1] tcp: fix forever orphan socket caused by tcp_abort
> 
> BugLink: https://bugs.launchpad.net/bugs/2114965
> 
> SRU Justification:
> 
> [Impact]
> In BFB version DOCA_2.6.0_BSP_4.6.0_Ubuntu_22.04-2.20240114, container
> deletion via removal of its kubelet YAML from /etc/kubelet.d sometimes
> fails to complete. The process waits for the container to disappear from
> crictl ps, but the container remains in Running state indefinitely. This
> behavior is seen with container version 2.dev.50 and FW 32.40.0324.
> The issue appears to stem from a kernel bug affecting orphaned TCP
> sockets stuck in a zero-window state. These sockets are not closed and
> timers are not rescheduled, leading to "forever orphan" behavior that
> prevents resource cleanup.
> 
> [Fix]
> Backporting the upstream commit:
> bac76cf89816 ("tcp: fix forever orphan socket caused by tcp_abort")
> This commit removes a conditional check on SOCK_DEAD in tcp_abort,
> allowing proper closure of orphaned sockets and preventing indefinite
> stalling. Backporting is needed as the error handling and logging
> methods differ from the original upstream code.
> 
> [Test Case]
> Compile tested on BF 5.15.
> Further testing includes reproducing the issue by removing the pod's
> YAML from /etc/kubelet.d and monitoring container termination using
> crictl ps.  With the patch applied, the container should no longer
> remain stuck in Running state.
> 
> [Regression Potential]
> The patch targets a specific edge case in TCP socket handling, and after
> backporting, it is as close as possible to the original upstream commit.
> However, since the change removes a check that previously avoided
> closing SOCK_DEAD sockets, there's a small risk if other kernel paths
> still rely on the earlier behavior. This could theoretically lead to
> unexpected side effects in force-close logic if assumptions about socket
> state are violated. Also, the backport is not an absolute match for the
> original commit, and so there's a possibility for unexpected behavior in
> edge cases related to socket teardown.
> 
> Xueming Feng (1):
>    tcp: fix forever orphan socket caused by tcp_abort
> 
>   net/ipv4/tcp.c | 23 ++++++++++++++---------
>   1 file changed, 14 insertions(+), 9 deletions(-)
> 
> --
> 2.34.1
>