growpart changes diskid of mbr disks
Bug #1817302 reported by
Steve Langasek
This bug affects 1 person
| Affects | Status | Importance | Assigned to | Milestone | |
|---|---|---|---|---|---|
| util-linux (Ubuntu) |
Fix Released
|
Undecided
|
Unassigned | ||
Bug Description
When growpart is run against a disk with a dos partition table, it evidently changes the disk id in the MBR. This was noticed because the diskid is part of the "PARTUUID" that is synthesized for DOS partitions (unlike GPT, which has UUIDs for each partition as part of the partition table).
This means that if someone is using root=PARTUUID=foo on the kernel commandline, the cloud image will successfully boot exactly once, and subsequently fail to boot because the partition uuid has changed.
I don't know at this point if this is a bug in cloud-utils or in sfdisk (util-linux).
Revision history for this message
| Juerg Haefliger (juergh) wrote | #1 |
| no longer affects: | cloud-utils (Ubuntu) |
Revision history for this message
| Juerg Haefliger (juergh) wrote | #2 |
| Changed in util-linux (Ubuntu): | |
| status: | New → Fix Committed |
Revision history for this message
| Launchpad Janitor (janitor) wrote | #3 |
| Changed in util-linux (Ubuntu): | |
| status: | Fix Committed → Fix Released |
To post a comment you must log in.
On 32-bit sfdisk fails to parse the label-id if the MSB is set and thus generates a new one. We happen to be unlucky with our (i386) cloud image in that the original label-id has the MSB set. So when growpart run (which calls sfdisk), the disk ID is regenerated and subsequent boots fail because the kernel can't find the root device.