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Date: Tue, 17 Jun 2025 15:47:27 +0200
From: Greg KH <gregkh@linuxfoundation.org>
To: Brett Sheffield <bacs@librecast.net>
Cc: stable@vger.kernel.org, regressions@lists.linux.dev
Subject: Re: 6.12.y longterm regression - IPv6 UDP packet fragmentation
Message-ID: <2025061745-calamari-voyage-d27a@gregkh>
References: <aElivdUXqd1OqgMY@karahi.gladserv.com>
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In-Reply-To: <aElivdUXqd1OqgMY@karahi.gladserv.com>

On Wed, Jun 11, 2025 at 01:04:29PM +0200, Brett Sheffield wrote:
> Hello Stable Maintainers,
> 
> Longterm kernel 6.12.y backports commit:
> 
> - a18dfa9925b9ef6107ea3aa5814ca3c704d34a8a "ipv6: save dontfrag in cork"

It's also in older kernels:
	5.10.238
	5.15.185
	6.1.141
	6.6.93

> but does not backport these related commits:
> 
> - 54580ccdd8a9c6821fd6f72171d435480867e4c3 "ipv6: remove leftover ip6 cookie initializer"
> - 096208592b09c2f5fc0c1a174694efa41c04209d "ipv6: replace ipcm6_init calls with ipcm6_init_sk"
> 
> This causes a regression when sending IPv6 UDP packets by preventing
> fragmentation and instead returning EMSGSIZE. I have attached a program which
> demonstrates the issue.

Should we backport thse two to all of the other branches as well?

thanks,

greg k-h