Fresh install  of 11.10

os-prober hangs on /usr/lib/os-probes/50mounted-tests repeatedly with many package installs/removals, kernel upgrades, grub updates, etc.  
because of ntfs disagreements about /dev/sda2

I've learned I needed to kill  pstree of 50mounted-tests repeatedly to unfreeze, and then often installations fail due to half-installed state.

os-prober hangs on /usr/lib/os-probes/50mounted-tests 


  ├─su-to-root,2151,master /usr/sbin/su-to-root -X -c /usr/sbin/startupmanager
  │   └─gksu,2158 -u root /usr/sbin/startupmanager
  │       └─sudo,2160,root -H -S -p GNOME_SUDO_PASS -u root -- /usr/sbin/startupmanager
  │           └─python,2161 /usr/sbin/startupmanager
  │               ├─{python},2164
  │               └─sh,2165 -c /usr/sbin/update-grub
  │                   └─grub-mkconfig,2166 /usr/sbin/grub-mkconfig -o /boot/grub/grub.cfg
  │                       └─30_os-prober,2486 /etc/grub.d/30_os-prober
  │                           └─30_os-prober,2499 /etc/grub.d/30_os-prober
  │                               ├─os-prober,2500 /usr/bin/os-prober
  │                               │   └─50mounted-tests,2633 /usr/lib/os-probes/50mounted-tests /dev/sda2
  │                               │       └─10freedos,2645 /usr/lib/os-probes/mounted/10freedos /dev/sda2 /var/lib/os-prober/mount fuseblk
  │                               │           ├─ls,2648 -1 /var/lib/os-prober/mount
  │                               │           └─grep,2649 -q -i ^kernel.sys$
  │                               ├─tr,2501   ^
  │                               └─paste,2502 -s -d  



==> /var/log/syslog <==
Jan 29 00:50:10 quant 50mounted-tests: debug: running subtest /usr/lib/os-probes/mounted/10qnx
Jan 29 00:50:10 quant 50mounted-tests: debug: running subtest /usr/lib/os-probes/mounted/20macosx
Jan 29 00:50:10 quant 10qnx: debug: /dev/sda2 is not a QNX4 partition: exiting
Jan 29 00:50:10 quant 50mounted-tests: debug: running subtest /usr/lib/os-probes/mounted/20macosx
Jan 29 00:50:10 quant macosx-prober: debug: /dev/sda2 is a FUSE partition
Jan 29 00:50:10 quant macosx-prober: debug: /dev/sda2 is a FUSE partition
Jan 29 00:53:51 quant kernel: [12361.016087] INFO: task 20macosx:27533 blocked for more than 120 seconds.
Jan 29 00:53:51 quant kernel: [12361.016092] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.

==> /var/log/kern.log <==
Jan 29 00:53:51 quant kernel: [12361.016087] INFO: task 20macosx:27533 blocked for more than 120 seconds.
Jan 29 00:53:51 quant kernel: [12361.016092] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
Jan 29 00:53:51 quant kernel: [12361.016096] 20macosx        D 00000000     0 27533   2633 0x00000000
Jan 29 00:53:51 quant kernel: [12361.016103]  f243ddb4 00000086 00006b91 00000000 f243dd82 f243dd58 c1761fe0 c186dec0
Jan 29 00:53:51 quant kernel: [12361.016112]  c186dec0 8a31804f 00000b0a f5005ec0 f31d4c80 f31d0cc0 00000000 e5928013
Jan 29 00:53:51 quant kernel: [12361.016121]  ee697ca8 00000005 00000005 f243de0c f243dec8 f243dd94 c113338e f243dea8
Jan 29 00:53:51 quant kernel: [12361.016130] Call Trace:
Jan 29 00:53:51 quant kernel: [12361.016142]  [<c113338e>] ? __follow_mount_rcu.isra.11+0x2e/0xb0
Jan 29 00:53:51 quant kernel: [12361.016148]  [<c113463f>] ? do_lookup+0x8f/0x270
Jan 29 00:53:51 quant kernel: [12361.016154]  [<c152c475>] schedule+0x35/0x50