netdev - Re: [PATCH v2] net: move somaxconn init from sysctl code

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Date:   Thu, 25 May 2017 13:12:31 -0400 (EDT)
From:   David Miller <davem@...emloft.net>
To:     roman.kapl@...go.com
Cc:     netdev@...r.kernel.org
Subject: Re: [PATCH v2] net: move somaxconn init from sysctl code

From: Roman Kapl <roman.kapl@...go.com>
Date: Wed, 24 May 2017 10:22:22 +0200

> The default value for somaxconn is set in sysctl_core_net_init(), but this
> function is not called when kernel is configured without CONFIG_SYSCTL.
> 
> This results in the kernel not being able to accept TCP connections,
> because the backlog has zero size. Usually, the user ends up with:
> "TCP: request_sock_TCP: Possible SYN flooding on port 7. Dropping request.  Check SNMP counters."
> If SYN cookies are not enabled the connection is rejected.
> 
> Before ef547f2ac16 (tcp: remove max_qlen_log), the effects were less
> severe, because the backlog was always at least eight slots long.
> 
> Signed-off-by: Roman Kapl <roman.kapl@...go.com>

This looks better, applied, thanks.