From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8F1DE21CC44 for ; Thu, 16 Oct 2025 06:25:45 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760595945; cv=none; b=QFH4HPiCd8hOSgV+qko3haevmcoifP0vCzFMLaIygWOO5Jyo6Evda0669z7AVG/ic2KUnD0M4sNmxjwkODS63xoMe18VN7fV3rDo4KJRm3OnTCC2DwmGCegYkC9d0chYCVp62PHJLv4mBqDg8mhAZukqGucjJZcNoM72zNkQemE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760595945; c=relaxed/simple; bh=1m4Hk7EVBiUQT3fUtyJl5ICcWL7F5BpX7wQLf6O0c1A=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=NG786nQA9VO+TA5tczBuxlnWox+sv80bRzUGpE13EPd3VdH72duG1HUzR1FvzfiY0HpPiJ30za/dGVLZumYq7EINNHt0RgP32YcVTYKL0Zz1GYJ/lModQKRDOnac3xzppPmbmNZHzpwQAG8ellh6ziaJ/Dt2k63oujvhMvX6Ye0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=DlyR1g5J; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="DlyR1g5J" Received: by smtp.kernel.org (Postfix) with ESMTPSA id AB926C4CEF1; Thu, 16 Oct 2025 06:25:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1760595945; bh=1m4Hk7EVBiUQT3fUtyJl5ICcWL7F5BpX7wQLf6O0c1A=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=DlyR1g5JOem+OB3HHV2dIHVpxfapSN3mz5BsdAj0k6H32Xn+4fgiYwZSF6z8MXYjx KD7Z6Y/E5bpvE6ftdw804nUxlQsyfDqxlmyreVhWyChQjZVFxXqMbHEMaJGN7nUGnG 3dkXCnMdAdptBnvL27tcQMz6/RSBC/GsBC61+LsU= Date: Thu, 16 Oct 2025 08:25:41 +0200 From: Greg Kroah-Hartman To: Jakub Kicinski Cc: Cynthia , "Rafael J. Wysocki" , Danilo Krummrich , netdev@vger.kernel.org Subject: Re: [REGRESSION] in 6.17, failing __dev_change_net_namespace+0xb89/0xc30 Message-ID: <2025101649-lid-cancel-4a69@gregkh> References: <01070199e22de7f8-28f711ab-d3f1-46d9-b9a0-048ab05eb09b-000000@eu-central-1.amazonses.com> <20251015133120.7ef53b20@kernel.org> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20251015133120.7ef53b20@kernel.org> On Wed, Oct 15, 2025 at 01:31:20PM -0700, Jakub Kicinski wrote: > On Tue, 14 Oct 2025 10:04:43 +0000 Cynthia wrote: > > When I updated my machine to the newest kernel, a bug started to appear. > > The system does not panic, but an error kept happening in dmesg. > > > > The bug happens with LXC/Incus when it tries to start a new container. > > (but probably other things are affected too) > > > > > > Steps to Reproduce: the bug can be reproduced in a libvirt VM, no need > > for a specific system. Also I suspect the bug is also > > architecture-independent, but I cannot verify that. > > 1) Install ArchLinux (all dependencies are available). I was testing > > with vanilla kernel, so any linux distro should be affected. > > https://aur.archlinux.org/packages/linux-mainline can be installed, this > > is the vanilla kernel with a generally good kernel config for most PCs. > > 2) Install LXC/Incus (pacman -S incus) > > 3) configure incus and start a container: > > usermod -v 1000000-1000999999 -w 1000000-1000999999 root && > > incus admin init && > > incus launch images:debian/12 first # start a container > > 4) Previous step should trigger incus to do namespaces. I'm not sure > > what syscall is causing the bug, I do not have a mini C program. These > > steps should be enough to see the log in the dmesg. > > > > I also did a git bisect, the first commit to have this bug is this: > > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=0c17270f9b920e4e1777488f1911bbfdaf2af3be > > > > I initially reported this bug on Bugzilla, but after seeing 6 year old > > bugs there, I'm not sure if that platform is still in use. > > https://bugzilla.kernel.org/show_bug.cgi?id=220649 > > > > Since my initial report, 6.17.2 was released, the bug is still happening. > > > > I'm attaching 2 files: > > dmesg_slice: the slice of dmesg containing the problematic frame (on a > > bare-metal linux with AMD srso mitigation disabled) > > bisect_log: a log of the git bisect process > > Thanks a lot for bisecting! Looking at the code my guess is that sysfs > gives us ENOENT when we try to change owner of a file that isn't > visible. Adding sysfs maintainers - should sysfs_group_attrs_change_owner() > call is_visible before trying to touch the attr? Oh, I never considered that call-path, and given that I haven't seen a bug report about this yet, it's pretty rare :) So yes, that should be checked. Can anyone knock up a patch for this? I'm busy all today with other stuff, sorry. greg k-h