Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Date:   Thu, 15 Feb 2018 13:19:20 -0700
From:   Keith Busch <keith.busch@intel.com>
To:     Julien Durillon <julien@durillon.xyz>
Cc:     linux-kernel@vger.kernel.org
Subject: Re: [BUG? NVME Linux-4.15] Dracut loops indefinitely with 4.15
Message-ID: <20180215201919.GA7076@localhost.localdomain>
References: <CAPVZMnqi0dF1u=Q223trP=mtvYd80Ydp5wamtz3Vt3xhRY-FEQ@mail.gmail.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <CAPVZMnqi0dF1u=Q223trP=mtvYd80Ydp5wamtz3Vt3xhRY-FEQ@mail.gmail.com>
User-Agent: Mutt/1.9.1 (2017-09-22)
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Thu, Feb 15, 2018 at 02:49:56PM +0100, Julien Durillon wrote:
> I opened an issue here:
> https://github.com/dracutdevs/dracut/issues/373 for dracut. You can
> read there how dracuts enters an infinite loop.
> 
> TL;DR: in linux-4.14, trying to find the last "slave" of /dev/dm-0
> ends with a maj:min of "249:0" which does not exist in /sys/dev/block.
> In linux-4.15, the same thing loops as "249:0" exists.

The problem is dracut assumes the 'dev' file for an nvme namespace's
parent device contains a maj:min for a block device. It's actually a
character device, and its maj:min happens to also be be the same as the
device mapper's block device.