kern/52916: vinum causes panic after start/stop/... cycle, easy to reproduce

[Pawel Malachowski]

>Number:         52916
>Category:       kern
>Synopsis:       vinum causes panic after start/stop/... cycle, easy to reproduce
>Confidential:   no
>Severity:       critical
>Priority:       high
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Tue Jun 03 15:40:06 PDT 2003
>Closed-Date:
>Last-Modified:
>Originator:     Pawe³ Ma³achowski
>Release:        FreeBSD 4.8-STABLE i386
>Organization:
ZiN
>Environment:
FreeBSD  4.8-RELEASE FreeBSD 4.8-RELEASE #0: Thu Apr  3 10:53:38 GMT 2003
root at freebsd-stable.sentex.ca:/usr/obj/usr/src/sys/GENERIC  i386

	
>Description:
Both 4.8-RELEASE and fresh 4.8-STABLE (on two different machines) catch
kernel panic when I try something like:
vinum start;vinum stop;vinum start;vinum stop;vinum start;vinum stop

It is very easy to reproduce.

4.8-STABLE was compiled with debug symbols, unfortunately there is no
crashdump. Panic message from 4.8-STABLE (vinum as kld):

vinum: loaded
vinum: no drives found
vinum: unloaded
vinum: loaded
vinum: no drives found
vinum: unloaded
vinum: loaded


Fatal trap 12: page fault while in kernel mode
fault virtual address   = 0xb7
fault code              = supervisor read, page not present
instruction pointer     = 0x8:0xc01bedc8
stack pointer           = 0x10:0xd5749dc4
frame pointer           = 0x10:0xd5749dd8
code segment            = base 0x0, limit 0xfffff, type 0x1b
                        = DPL 0, pres 1, def32 1, gran 1
processor eflags        = interrupt enabled, resume, IOPL = 0
current process         = 107 (syslogd)
interrupt mask          = none
trap number             = 12
panic: page fault

syncing disks...

Fatal trap 12: page fault while in kernel mode
fault virtual address   = 0xb7
fault code              = supervisor read, page not present
instruction pointer     = 0x8:0xc01bedc8
stack pointer           = 0x10:0xd5749b04
frame pointer           = 0x10:0xd5749b18
code segment            = base 0x0, limit 0xfffff, type 0x1b
                        = DPL 0, pres 1, def32 1, gran 1
processor eflags        = interrupt enabled, resume, IOPL = 0
current process         = 107 (syslogd)
interrupt mask          = bio
trap number             = 12
panic: page fault
Uptime: 1m6s


So I compiled vinum statically into kernel,

# vinum start;vinum stop;vinum start;vinum stop;
** no drives found: No such file or directory
Can't unload vinum: No such file or directory
** no drives found: No such file or directory
Can't unload vinum: No such file or directory

and it crashed again with message like this:

vinum: no drives found
vinum: no drives found


Fatal trap 12: page fault while in kernel mode
fault virtual address   = 0xb7
fault code              = supervisor read, page not present
instruction pointer     = 0x8:0xc01cc204
stack pointer           = 0x10:0xd51e0e6c
frame pointer           = 0x10:0xd51e0e80
code segment            = base 0x0, limit 0xfffff, type 0x1b
                        = DPL 0, pres 1, def32 1, gran 1
processor eflags        = interrupt enabled, resume, IOPL = 0
current process         = 6 (syncer)
interrupt mask          = bio
trap number             = 12
panic: page fault

	
>How-To-Repeat:
Install minimal 4.8-RELEASE from ISO, type:
vinum start;vinum stop;vinum start;vinum stop;vinum start;vinum stop;
few times.

Note, creating vinum objects is not necessary!

Also note:
kldload vinum;kldunload vinum;kldload vinum;kldunload vinum;
doesn't produce panic on my machine.

I caught first panic when I tried `vinum stop' while reviving subdisk
(however, vinum was loaded/unloaded few times earlier cause configuration
was obliterated).

	
>Fix:
Unknown.
	


>Release-Note:
>Audit-Trail:
>Unformatted: