Bug#788062: os-prober corrupts LVs/partitions while being mounted inside a VM

["Andreas Thalhammer (AIFB)" <andreas.thalhammer@kit.edu>]

We can confirm this Bug (Debian 8.0 Jessie on VM host and guests).

os-prober version: 1.65 amd64

VM host
=====

Sep  7 14:43:19 vm-host os-prober: debug: running 
/usr/lib/os-probes/50mounted-tests on /dev/mapper/vm1-disk

Inside VM1
=====
Sep  7 14:43:20 vm1 kernel: [4552906.712287] end_request: I/O error, dev 
vda, sector 5125812120


We had two out of five EXT4 VM filesystems corrupted in a single run of 
"apt-get upgrade". The filesystems automatically switched to read-only 
mode shortly after the first errors and we rebooted both VMs (fsck 
automatically enabled: orphaned inodes and some inodes had to be removed).

We regard this bug as highly critical.