Red Hat Bugzilla – Bug 118990
Computer hangs when unmounting an LVM snapshot & quickly lvremove'ing it
Last modified: 2007-11-30 17:10:38 EST
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Description of problem:
I wrote a script to make nightly backups by taking a LVM snapshot.
This usually works but, sometimes the machine gets (almost) completely
locked up. After some research, I think the problem is some kind of
race when doing a lvremove -f immediately after unmounting the snapshot.
Here is part of my script:
lvcreate -l 250 -s -n mysnap /dev/vg00/var
mount -o ro /dev/vg00/mysnap /mnt/snapshot
lvremove -f /dev/vg00/mysnap
When locked, I can still ping the machine, and TCP handshaking seems
to work to some point, but no more (All network services time out
eventually). Also, keyboard and mouse don't respond.
Meanwhile, I inserted a 'sleep 5' between unmount and lvremove as a
workaround. I hope it will do the trick.
Our machine has 2 physical processors, with hyperthreading enabled on
Version-Release number of selected component (if applicable):
Steps to Reproduce:
1. lvcreate -l num -s -n blah /dev/vg00/blah
2. mount /dev/vg00/blah /mnt/blah
3. umount /mnt/blah
4. lvremove -f /dev/vg00/blah
Actual Results: The computer got locked up. I can't tell for sure if
an oops ocurred, since the console is blanked and the keyboard doesn't
Expected Results: Well...
This is a 4 way machine (2 hyperthreaded Xeons)
*** This bug has been marked as a duplicate of 109497 ***
Changed to 'CLOSED' state since 'RESOLVED' has been deprecated.