I found the reason for the bug. The script we used to test snapshotting used xfs and made a xfs_freeze just before snapshotting. This triggers a race condition inside the kernel which tries to freeze the filesystem to do the snapshot.
IMHO the kernel should check if the filesystem is already frozen and maybe increase a "freeze counter" to avoid the race. ** Attachment added: "the script with xfs_freeze commented out" http://librarian.launchpad.net/5601927/lvm-test -- system crash when creating more than one snapshot of a lvm volume https://launchpad.net/bugs/76421 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
