Hi there, 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. ## My configuration I'm using a nvme ssd disk named "nvme0n1". It has two partitions: an EFI one and a luks encrypted btrfs volume. So in /dev I have /dev/dm-0 that is referenced to by /dev/mapper/root. /dev/mapper/root -> /dev/dm-0 is the mapped un-encrypted "/dev/nvme0n1p2" volume used as a btrfs volume. ## My problem *Before* linux-4.15, `stat /dev/dm-0` displays: File: /dev/dm-0 Size: 0 Blocks: 0 IO Block: 4096 block special file Device: 6h/6d Inode: 2768 Links: 1 Device type: fa,0 Access: (0660/brw-rw----) Uid: ( 0/ root) Gid: ( 6/ disk) Access: 2018-02-12 17:49:46.020513274 +0100 Modify: 2018-02-12 17:49:46.020513274 +0100 Change: 2018-02-12 17:49:46.020513274 +0100 Birth: - So the device type is "fa,0", which is translated by dracut as "250:0". *Starting at* linux-4.15, `stat /dev/dm-0` displays: File: /dev/dm-0 Size: 0 Blocks: 0 IO Block: 4096 block special file Device: 6h/6d Inode: 17795 Links: 1 Device type: f9,0 Access: (0660/brw-rw----) Uid: ( 0/ root) Gid: ( 6/ disk) Access: 2018-02-15 14:38:56.570529189 +0100 Modify: 2018-02-15 14:38:56.570529189 +0100 Change: 2018-02-15 14:38:56.570529189 +0100 Birth: - So the device type is "f9,0", which is translated by dracut as "249:0". I'm posting it here because I don't understand why the kernel changed the device type. Is it intended? Regards, -- Julien Durillon