Bug 815469

Summary: Floppy driver cause kernel panic in slow virtualized environment
Product: [Fedora] Fedora Reporter: Pavel Hrdina <phrdina>
Component: kernelAssignee: Kernel Maintainer List <kernel-maint>
Status: CLOSED RAWHIDE QA Contact: Fedora Extras Quality Assurance <extras-qa>
Severity: low Docs Contact:
Priority: unspecified    
Version: rawhideCC: gansalmon, itamar, jonathan, kernel-maint, madhu.chinakonda
Target Milestone: ---   
Target Release: ---   
Hardware: Unspecified   
OS: Linux   
Whiteboard:
Fixed In Version: Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of:
: 815472 (view as bug list) Environment:
Last Closed: 2012-08-10 19:39:29 UTC Type: Bug
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Bug Depends On:    
Bug Blocks: 815472    
Attachments:
Description Flags
backtrace-rhel6
none
backtrace-fedora16 none

Description Pavel Hrdina 2012-04-23 16:30:46 UTC 
Description of problem:
Floppy driver cause kernel panic in slow virtualized environment.

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

How reproducible:
75%

Steps to Reproduce:
1. run qemu without kvm support and with floppy image inserted
2. in guest run "modprobe floppy" and then "mount /dev/fd0 /mnt"
3. mount command cause kernel panic, but not always
  
Actual results:
kenrel panic

Expected results:
mount floppy without kernel panic
Comment 1 Josh Boyer 2012-04-23 16:34:59 UTC 
Can you attached the backtrace?  Also, which kernel version(s)?
Comment 2 Pavel Hrdina 2012-04-23 19:49:55 UTC 
Created attachment 579675 [details]
backtrace-rhel6

Here is the backtrace on rhel6.3 you asked for and kernel version is 2.6.32-262.el6.x86_64
Comment 3 Josh Boyer 2012-04-23 20:00:34 UTC 
(In reply to comment #2)
> Created attachment 579675 [details]
> backtrace
> 
> Here is the backtrace on rhel6.3 you asked for and kernel version is
> 2.6.32-262.el6.x86_64

You reported this against Fedora rawhide.  Does it happen there, or is this a RHEL-only bug?  If it happens in Fedora, can you attach the Fedora kernel backtrace?
Comment 4 Pavel Hrdina 2012-04-23 20:02:27 UTC 
Created attachment 579681 [details]
backtrace-fedora16

Here is the backtrace on fedora16 and kernel version is 3.3.0-8.fc16.x86_64
Comment 5 Josh Boyer 2012-08-10 19:39:29 UTC 
I tried this with the latest rawhide kernel on a non-KVM guest.  I ran:

modprobe floppy; mount /dev/fd0 /mnt; umount /mnt; modprobe -r floppy

several times and never got an oops.  There have been a number of block and floppy related changes since 3.3.

I'm going to close this bug out as fixed.  If you can recreate with the latest rawhide kernel, please reopen.

I do, however, question how much we care about this specific use case.  AFAIK, RHEL doesn't support non-KVM qemu and while Fedora might, it's use is rather limited particularly with floppy images.