Bug 431806

Summary: kernel BUG at block/cfq-iosched.c:1147 on USB disconnect
Product: [Fedora] Fedora Reporter: Mace Moneta <moneta.mace>
Component: kernelAssignee: Kernel Maintainer List <kernel-maint>
Status: CLOSED CURRENTRELEASE QA Contact: Fedora Extras Quality Assurance <extras-qa>
Severity: medium Docs Contact:
Priority: low    
Version: 8CC: jmoyer
Target Milestone: ---   
Target Release: ---   
Hardware: i686   
OS: Linux   
Whiteboard:
Fixed In Version: 2.6.24.3-34.fc8 Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2008-03-19 23:26:49 UTC Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
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Description Flags
Applicable /var/log/messages entries none

Description Mace Moneta 2008-02-07 01:22:52 UTC 
Description of problem:

I plugged in an external USB drive, mounted it, performed a backup, unmounted
it, then disconnected it.  Kernel bug appears in the log.

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

2.6.23.14-107.fc8

How reproducible:

intermittent

Steps to Reproduce:
1.Plug in external USB 2.0 drive
2.Mount external drive
3.Write to external drive
4.Unmount external drive
5.Unplug external drive
  
Actual results:

Kernel bug

Expected results:

No kernel bug

Additional info:

A reboot is needed before USB devices can be used again.
Comment 1 Mace Moneta 2008-02-07 01:22:52 UTC 
Created attachment 294180 [details]
Applicable /var/log/messages entries
Comment 2 Mace Moneta 2008-02-07 02:00:58 UTC 
Just a note: Googling around, it looks like someone else has reported the same
issue in a Debian 2.6.23 kernel here:

http://groups.google.com/group/linux.debian.kernel/browse_thread/thread/34fb55a26f15ae88
Comment 3 Chuck Ebbert 2008-02-08 00:27:22 UTC 
cfq-iosched.c:
       BUG_ON(atomic_read(&cfqq->ref) <= 0);
Comment 4 Mace Moneta 2008-02-09 20:16:29 UTC 
I found kernel bug 9180 discusses this problem (two issues in the bug report). 
I was running ioniced at the time, so this looks like a good match.  A patch to
correct it is supposed to be available.

http://bugzilla.kernel.org/show_bug.cgi?id=9180
Comment 5 Mace Moneta 2008-03-19 23:26:49 UTC 
This appears to have been resolved in the 2.6.24.3 based kernels, as I can no
longer recreate the problem.  Closing.