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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
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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.