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From: "Arnd Bergmann" <arnd@arndb.de>
To: "Sebastian Andrzej Siewior" <bigeasy@linutronix.de>
Cc: "Mickaël Salaün" <mic@digikod.net>,
	"Arnd Bergmann" <arnd@kernel.org>,
	"Paul Moore" <paul@paul-moore.com>,
	"James Morris" <jmorris@namei.org>,
	"Serge E. Hallyn" <serge@hallyn.com>,
	"Tingmao Wang" <m@maowtm.org>,
	"Justin Suess" <utilityemal77@gmail.com>,
	"Günther Noack" <gnoack@google.com>,
	linux-security-module@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH] [v2] landlock: work around gcc-16 -Wuninitialized warning
Date: Thu, 17 Sep 2026 12:26:17 +0200	[thread overview]
Message-ID: <1192c2df-d39a-4d43-ad57-68b0167759f5@app.fastmail.com> (raw)
In-Reply-To: <20260917070915.Ix8TOn5Y@linutronix.de>

[-- Attachment #1: Type: text/plain, Size: 1416 bytes --]

On Thu, Sep 17, 2026, at 09:09, Sebastian Andrzej Siewior wrote:
> On 2026-09-16 23:06:30 [+0200], Arnd Bergmann wrote:
>> As far as I can tell, 16.2 is still affected, even though it should be
>> fixed in HEAD. gcc-16.3 won't be released until spring 2027 though.
>> 
>> It is possible that there are additional configuration options that
>> have to be set just right to reproduce the issue. I've attached a
>> configuration that triggered it for me this week.
>
> This is from v7.2. I tried this and v7.3-rc3 and did not notice a
> warning (other than unrelated stack size from drm). I did notice:
>
> -CONFIG_CC_VERSION_TEXT="x86_64-linux-gcc (GCC) 16.2.0"
> +CONFIG_CC_VERSION_TEXT="gcc (Debian 16.2.0-2) 16.2.0"
>  CONFIG_GCC_VERSION=160200
> -CONFIG_AS_VERSION=20285426
> +CONFIG_AS_VERSION=24700
> -CONFIG_LD_VERSION=20285426
> +CONFIG_LD_VERSION=24700
> +CONFIG_CC_HAS_MARCH_NATIVE=y
>
> which might be the culprit. There were other things, too, so the
> oldconfig was not clean (such as missing CONFIG_VIRTUALIZATION).

I checked again and found that this is a config that did produce
the issue a few weeks ago, but doesn't today for me.
I found a different config from this week and managed to reproduce
the problem on today's linux-next using both gcc-16.2 and gcc-17.0
from yesterday, so there is still a related issue that is not
fixed in gcc, even though one at least one of them was fixed.

      Arnd

[-- Attachment #2: config.gz --]
[-- Type: application/gzip, Size: 42783 bytes --]

  reply	other threads:[~2026-09-17 10:27 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-09-15 20:10 [PATCH] [v2] landlock: work around gcc-16 -Wuninitialized warning Arnd Bergmann
2026-09-16  8:49 ` Sebastian Andrzej Siewior
2026-09-16 12:25   ` Mickaël Salaün
2026-09-16 21:06     ` Arnd Bergmann
2026-09-17  7:09       ` Sebastian Andrzej Siewior
2026-09-17 10:26         ` Arnd Bergmann [this message]
2026-09-17 10:45           ` Sebastian Andrzej Siewior
2026-09-17 11:36             ` Arnd Bergmann
2026-09-18 13:55               ` Mickaël Salaün

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