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Date: Fri, 13 Aug 1999 12:26:41 +0200 (MET DST)
From: Peter Brevik <pb@ludd.luth.se>
To: FreeBSD-gnats-submit@freebsd.org
Subject: panic related (proberbly) to vnode

>Number:         13113
>Category:       kern
>Synopsis:       panic related (proberbly) to vnode
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    freebsd-bugs
>State:          closed
>Quarter:        
>Keywords:       
>Date-Required:  
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Fri Aug 13 03:30:01 PDT 1999
>Closed-Date:    Tue May 16 15:11:18 PDT 2000
>Last-Modified:  Tue May 16 15:12:18 PDT 2000
>Originator:     
>Release:        FreeBSD 2.2.7-RELEASE i386
>Organization:
<Organization of PR author (multiple lines)>
Confidential:   no
Synopsis:       Vnode system has a bug which may cause kernel panic
Severity:       serious
Priority:       low
Category:       kern
>Environment:
>Description:
 X-send-pr-version: 3.2
 
 
 Submitter-Id:   current-users
 Originator:     Peter
 Class:          sw-bug
 Environment:
 
 Extract from dmesg:
 
 CPU: Pentium II (quarter-micron) (348.49-MHz 686-class CPU)
   Origin = "GenuineIntel"  Id = 0x651  Stepping=1
   Features=0x183f9ff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,SEP,MTRR,PGE,MCA,CMOV,<b16>,<b17>,MMX,<b24>>
 real memory  = 67108864 (65536K bytes)
 avail memory = 63299584 (61816K bytes)
 .
 pcm0 at 0x220 irq 5 drq 1 on isa
 ESS1869 (rev 11, native mode)
 .
 wdc0 at 0x1f0-0x1f7 irq 14 on isa
 wdc0: unit 0 (wd0): <WDC AC36400L>
 wd0: 6149MB (12594960 sectors), 13328 cyls, 15 heads, 63 S/T, 512 B/S
 wdc1 at 0x170-0x177 irq 15 on isa
 wdc1: unit 0 (atapi): <COMPAQ  CDR-8335/0008>, removable, accel, dma, iordy
 wcd0: 1779/4134Kb/sec, 128Kb cache, audio play, 255 volume levels, ejectable tra
 y
 wcd0: no disc inside, unlocked
 wcd0:  mode 2 form 1(XA) 2, multisession, CD-DA read stream, C2, ISRC, UPC
 
 
 Description:
 
         I found my machine rebooted without any apparent reason. But then
         in the log the following is written:
 
 Aug 13 02:02:40 srv /kernel: panic: vref used where vget required
 Aug 13 02:02:40 srv /kernel: 
 Aug 13 02:02:40 srv /kernel: syncing disks... 10 10 done
 Aug 13 02:02:40 srv /kernel: Automatic reboot in 15 seconds - press a key on the console to abort
 Aug 13 02:02:40 srv /kernel: Rebooting...
 
         The only thing I can relate to this is a CD-rom image which I
         accidently mounted with "mount_cd9660 /dev/vn0 /mnt/test/". And
         ofcourse the last slash casues the phenomen where you can't unmount..
 
         So later to free the file I run "vnconfig -u /dev/vn0". But this leaves
         the vnode disc mount remaining without a disc file to relate to.
         I think the 2 o'clock maintaince routines (standard freebsd/unmodified)
         have somehow gotten the kernel to panic when accessing the discs.
 
         However, it seems it managed at least one night job previous night.
         (It might be the Friday 13'th fenomen :-)
 
         I think the vnode system should be immune to things like this.
      
 How-To-Repeat:
 
         vnconfig /dev/vn0 <filesystem-file>
         mount_cd9660 /dev/vn0 <mnt-point-path>
         vnconfig -u /dev/vn0
 
         Use find <mnt-point-path> or heavy disc access on the vnode system, I
         gues... (not tried).
 
 Fix:
 
         1) Don't unconfig vnode disc before unmount.
         2) Don't use vnode facility
         3) Make sure no process is accessing the disc which is in no man's
            land :)
 
 
>How-To-Repeat:
>Fix:
>Release-Note:
>Audit-Trail:
State-Changed-From-To: open->feedback 
State-Changed-By: green 
State-Changed-When: Fri Aug 13 15:59:04 PDT 1999 
State-Changed-Why:  
I'm almost certain this is fixed in 3.X/4.X. Try a non-ancient version of 
FreeBSD and see if it still exists. 
Responsible-Changed-From-To: gnats-admin->freebsd-bugs 
Responsible-Changed-By: peter 
Responsible-Changed-When: Sun Nov 28 07:16:28 PST 1999 
Responsible-Changed-Why:  
Misfiled PR 
State-Changed-From-To: feedback->closed 
State-Changed-By: hoek 
State-Changed-When: Tue May 16 15:11:18 PDT 2000 
State-Changed-Why:  
As noted by green, I believe this has been fixed in 3-stable and onwards. 
>Unformatted:
