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Date: Fri, 7 Sep 2018 04:38:25 +0100
From: Al Viro <viro@ZenIV.linux.org.uk>
To: Sasha Levin <Alexander.Levin@microsoft.com>
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Cc: ksummit <ksummit-discuss@lists.linuxfoundation.org>
Subject: Re: [Ksummit-discuss] [MAINTAINERS SUMMIT] Bug-introducing patches
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On Fri, Sep 07, 2018 at 01:49:31AM +0000, Sasha Levin via Ksummit-discuss wrote:

> This is a *huge* reason why we see regressions in Stable. Take a look at
> https://lists.linuxfoundation.org/pipermail/ksummit-discuss/2018-September/005287.html
> for a list of recent user visible regressions the CoreOS folks have
> observed this year. Do you want to know when they were merged? Let me
> help you: all but one were merged in -rc5 or later.

	Umm...  Looking.  Looks like the nastiest one in there is a TCP
regression, caused by inclusion of "tcp: avoid integer overflows in
tcp_rcv_space_adjust()" in 4.14.48.  Fixed by inclusion of "tcp: do not
overshoot window_clamp in tcp_rcv_space_adjust()" into 4.14.50.  

	Note that in mainline the latter is actually a sodding *PARENT*
of the former, so no amount of soaking in, testing, etc. would have caught
the problem.  Simply because there wasn't one.

	That, presumably, is the one exception you mention?  I honestly
went by the apparent impact - digging through their (github) user interface
is not my idea of fun ;-/

	Could you post summaries of the other 4?  Or links to such, if that
got covered at some point in that thread...