Bug 143066

Summary: Race condition causes umount /sys to fail
Product: [Fedora] Fedora Reporter: Pierre Ossman <pierre-bugzilla>
Component: mkinitrdAssignee: Peter Jones <pjones>
Status: CLOSED WORKSFORME QA Contact: David Lawrence <dkl>
Severity: high Docs Contact:
Priority: medium    
Version: 3   
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Hardware: All   
OS: Linux   
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Fixed In Version: Doc Type: Bug Fix
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Last Closed: 2005-08-02 17:04:20 UTC Type: ---
Regression: --- Mount Type: ---
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Description Flags
Example initrd none

Description Pierre Ossman 2004-12-16 10:04:52 UTC 
Description of problem:

There exists some sort of race condition in the initrd script
generated by mkinitrd. Sometimes umount /sys fails with error EBUSY.
udev probably doesn't close something fast enough. Adding a 'sleep 1'
just before the umount makes the problem go away.
The problem only appears in the specific case outlined in the
instructions.


Version-Release number of selected component (if applicable):
4.1.18-2


How reproducible:

Almost every time. (~9 out of 10 times)


Steps to Reproduce:

1. Power off laptop
2. Remove AC power
3. Boot up
4. Observe error -16 when trying to umount /sys


Actual results:

Extra /sys mounted when looking in /proc/mounts


Expected results:

Only one /sys mounted.
Comment 1 Pierre Ossman 2004-12-16 10:05:36 UTC 
Extra information can be found at:

http://www.bughost.org/bugzilla/show_bug.cgi?id=464
Comment 2 Jeremy Katz 2004-12-20 17:40:23 UTC 
Can you attach one of your initrds?  I can't see how this would happen
in the usual case and before slowing down bootup, I'd like to try to
figure out what in sysfs is being accessed during the initrd
Comment 3 Pierre Ossman 2004-12-20 18:15:53 UTC 
Created attachment 108914 [details]
Example initrd
Comment 4 Jeremy Katz 2004-12-20 18:22:05 UTC 
Hmmm, have you seen this with anything other than XFS root fs's?
Comment 5 Pierre Ossman 2004-12-20 18:43:08 UTC 
It is only on one machine that this bug causes any kind of problem. So
I don't know if this has appeared on any other machine.
And changing the root fs isn't something I do on a daily basis so the
machine in question has not experienced anything but XFS.
Comment 6 Peter Jones 2005-04-18 20:11:21 UTC 
Does this still happen for you in fc4t2?
Comment 7 Pierre Ossman 2005-04-19 17:21:10 UTC 
The problem went away when I changed to ext3 on the machine. I'm no longer able
to replicate the problem so I cannot test if there has been a change for fc4t2.
Sorry.