So /usr/lib/udev/rules.d/60-persistent-storage-dm.rules is responsible for creating the /dev/disk/by-id/dm-uuid-* symlinks:
root@plucky:~# grep -rn "disk/by-id/dm-uuid" /usr/lib/udev/rules.d/ /usr/lib/udev/rules.d/60-persistent-storage-dm.rules:18:ENV{DM_UUID}=="?*", SYMLINK+="disk/by-id/dm-uuid-$env{DM_UUID}" That symlink is dependent on a non-empty `DM_UUID` udev environment variable. That variable is set in /usr/lib/udev/rules.d/55-dm.rules: root@plucky:~# grep -rn "ENV{DM_UUID}=[^=]" /usr/lib/udev/rules.d/ /usr/lib/udev/rules.d/55-dm.rules:133:TEST=="dm", ENV{DM_NAME}="$attr{dm/name}", ENV{DM_UUID}="$attr{dm/uuid}", ENV{.DM_SUSPENDED}="$attr{dm/suspended}" So if that environment variable is not set, that's one reason why the symlinks would not be created. A reason that variable is not set would be that /sys/block/dm-N/dm (or /sys/block/dm-N/dm/uuid) does not exist. Can you check for the existence of those things in /sys/, and maybe paste the output of `udevadm info /sys/block/dm-N` for each N? -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/2102236 Title: plucky/s390x (with root disk on dm?) does not come up after kernel update + reboot Status in Ubuntu on IBM z Systems: New Status in linux package in Ubuntu: New Status in lvm2 package in Ubuntu: New Bug description: While using the plucky daily from March 12 (that still comes with kernel 6.12) (and working around LP#2101831, by forcing the installation to not apply any updates) I get a system installed, which is at kernel level 6.12. Since 6.14 is out (in plucky release) since yesterday (March 12th) I tried to upgrade from 6.12 to 6.14, and the update itself seemed to be smooth (I couldn't find any errors while doing a full-upgrade in the terminal - see attached logs). But after executing a reboot, the system (in 3 different configurations, that use dm) does not come up again, and ends up in busybox, complaining that the root device couldn't be found: # s1lp15 FCP/SCSI multipath with LVM ALERT! /dev/disk/by-id/dm-uuid-LVM-SlleSC5YA825VOM3t0KHBVFrLJcNWsnwZsObNziIB9Bk2mSVphnuTEOQ2eFiBbE1 does not exist. Dropping to a shell! # s1lp15 2DASDs with LVM: ALERT! /dev/disk/by-id/dm-uuid-LVM-ePTbsojYPfgMacKXwpIMNMvxk80qGzlPhRYw7DJlovmqHyla9TK6NGc70p1JN29b does not exist. Dropping to a shell! # s1lp15 FCP/SCSI Multipath no LVM ALERT! /dev/disk/by-id/dm-uuid-part1-mpath-36005076306ffd6b60000000000002603 does not exist. Dropping to a shell! However, using a single disk without dm (so: no multipath, no lvm) the system is able to come up again after the reboot (after a kernel upgrade). # s1lp15 single DASD no LVM here the root device is: root=/dev/disk/by-path/ccw-0.0.260b-part1 and it exists. In the 3 different cases that (that repeatedly fail) "/dev/disk/by-id" is missing. I am not sure yet what's causing this, it can be an issue with the device-mapper/lvm2 but also udev rules or kernel. So maybe I need to add the kernel as affected component too (for now). To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu-z-systems/+bug/2102236/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp