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Sender: Guenter Roeck <groeck7@gmail.com>
Subject: Re: [PATCH 000/190] Revertion of all of the umn.edu commits
To:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        linux-kernel@vger.kernel.org
Cc:     Linus Torvalds <torvalds@linux-foundation.org>,
        Aditya Pakki <pakki001@umn.edu>, Kangjie Lu <kjlu@umn.edu>,
        Qiushi Wu <wu000273@umn.edu>, x86@kernel.org,
        Bjorn Helgaas <bhelgaas@google.com>,
        "Rafael J. Wysocki" <rjw@rjwysocki.net>,
        Arnd Bergmann <arnd@arndb.de>, David Airlie <airlied@linux.ie>,
        Michael Turquette <mturquette@baylibre.com>,
        Bjorn Andersson <bjorn.andersson@linaro.org>,
        Linus Walleij <linus.walleij@linaro.org>,
        Bartosz Golaszewski <bgolaszewski@baylibre.com>,
        Daniel Vetter <daniel@ffwll.ch>,
        Jean Delvare <jdelvare@suse.com>,
        Jiri Kosina <jikos@kernel.org>, Will Deacon <will@kernel.org>,
        Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
        Jakub Kicinski <kuba@kernel.org>,
        "David S. Miller" <davem@davemloft.net>,
        Johan Hovold <johan@kernel.org>,
        Jiri Slaby <jirislaby@kernel.org>,
        Pablo Neira Ayuso <pablo@netfilter.org>,
        Johannes Berg <johannes@sipsolutions.net>,
        Takashi Iwai <tiwai@suse.com>
References: <20210421130105.1226686-1-gregkh@linuxfoundation.org>
From:   Guenter Roeck <linux@roeck-us.net>
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Message-ID: <4afeeb49-620d-5a9d-29fc-453f6118a944@roeck-us.net>
Date:   Wed, 21 Apr 2021 06:56:49 -0700
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On 4/21/21 5:57 AM, Greg Kroah-Hartman wrote:
> I have been meaning to do this for a while, but recent events have
> finally forced me to do so.
> 
> Commits from @umn.edu addresses have been found to be submitted in "bad
> faith" to try to test the kernel community's ability to review "known
> malicious" changes.  The result of these submissions can be found in a
> paper published at the 42nd IEEE Symposium on Security and Privacy
> entitled, "Open Source Insecurity: Stealthily Introducing
> Vulnerabilities via Hypocrite Commits" written by Qiushi Wu (University
> of Minnesota) and Kangjie Lu (University of Minnesota).
> 

Sigh. As if this wouldn't be a problem everywhere.

> Because of this, all submissions from this group must be reverted from
> the kernel tree and will need to be re-reviewed again to determine if
> they actually are a valid fix.  Until that work is complete, remove this
> change to ensure that no problems are being introduced into the
> codebase.
> 
> This patchset has the "easy" reverts, there are 68 remaining ones that
> need to be manually reviewed.  Some of them are not able to be reverted
> as they already have been reverted, or fixed up with follow-on patches
> as they were determined to be invalid.  Proof that these submissions
> were almost universally wrong.
> 
> I will be working with some other kernel developers to determine if any
> of these reverts were actually valid changes, were actually valid, and
> if so, will resubmit them properly later.  For now, it's better to be
> safe.
> 
> I'll take this through my tree, so no need for any maintainer to worry
> about this, but they should be aware that future submissions from anyone
> with a umn.edu address should be by default-rejected unless otherwise
> determined to actually be a valid fix (i.e. they provide proof and you
> can verify it, but really, why waste your time doing that extra work?)
> 
> thanks,
> 
> greg k-h
> 
[ ... ]
>   Revert "hwmon: (lm80) fix a missing check of bus read in lm80 probe"

I see

9aa3aa15f4c2 hwmon: (lm80) fix a missing check of bus read in lm80 probe
c9c63915519b hwmon: (lm80) fix a missing check of the status of SMBus read

The latter indeed introduced a problem which was later fixed with

07bd14ccc304 hwmon: (lm80) Fix missing unlock on error in set_fan_div()

I guess that was part of the experiment. I don't see a problem with the
patch that is being reverted, but it is not extremely valuable either,
so I don't mind the revert. It is not valuable enough to re-apply it later
either.

FWIW, I didn't see the problem with the second patch even when re-reviewing
it, which makes me suspect that they introduced missing-unlock problems on
purpose. It is important to keep that in mind when re-reviewing the patches.
Also, it may be part of the pattern that they introduced one or more valid
patches followed by a malicious one into the same subsystem on purpose.

Guenter