Bug 143066 - Race condition causes umount /sys to fail
Race condition causes umount /sys to fail
Status: CLOSED WORKSFORME
Product: Fedora
Classification: Fedora
Component: mkinitrd (Show other bugs)
3
All Linux
medium Severity high
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Assigned To: Peter Jones
David Lawrence
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Depends On:
Blocks:
  Show dependency treegraph
 
Reported: 2004-12-16 05:04 EST by Pierre Ossman
Modified: 2007-11-30 17:10 EST (History)
0 users

See Also:
Fixed In Version:
Doc Type: Bug Fix
Doc Text:
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Clone Of:
Environment:
Last Closed: 2005-08-02 13:04:20 EDT
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RHEL 7.3 requirements from Atomic Host:
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Attachments (Terms of Use)
Example initrd (294.00 KB, application/octet-stream)
2004-12-20 13:15 EST, Pierre Ossman
no flags Details

  None (edit)
Description Pierre Ossman 2004-12-16 05:04:52 EST
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 05:05:36 EST
Extra information can be found at:

http://www.bughost.org/bugzilla/show_bug.cgi?id=464
Comment 2 Jeremy Katz 2004-12-20 12:40:23 EST
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 13:15:53 EST
Created attachment 108914 [details]
Example initrd
Comment 4 Jeremy Katz 2004-12-20 13:22:05 EST
Hmmm, have you seen this with anything other than XFS root fs's?
Comment 5 Pierre Ossman 2004-12-20 13:43:08 EST
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 16:11:21 EDT
Does this still happen for you in fc4t2?
Comment 7 Pierre Ossman 2005-04-19 13:21:10 EDT
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.

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