kern/101794: Setting plip as syncdev for pfsync causes kernel panic.

Ian yoitsmeremember at
Fri Aug 11 06:10:18 UTC 2006

>Number:         101794
>Category:       kern
>Synopsis:       Setting plip as syncdev for pfsync causes kernel panic.
>Confidential:   no
>Severity:       non-critical
>Priority:       medium
>Responsible:    freebsd-bugs
>State:          open
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Fri Aug 11 06:10:16 GMT 2006
>Originator:     Ian
>Release:        FreeBSD-6.1
FreeBSD 6.0-RELEASE i386  # originally discovered on
FreeBSD 6.1-RELEASE i386  # found to affect this release as well
When assigning the pfsync device (pfsync0) to the plip device (plip0) via the command `ifconfig pfsync0 syncdev plip0` the kernel panics with a "Fatal trap 12: page fault while in kernel mode".  This *might* only happen when plip has no IP configuration, as I have not tested it post ip configuration (many apologies).

The kernel has no debug options (sorry again!), but here's the info found on the screen post-mortem.

fault virtual address = 0x8
fault code            = supervisor read, page not present
instruction pointer   = 0x20:0xc04ca787
stack pointer         = 0x28:0xe35ebb7c
frame pointer         = 0x28:0xe35ebc2c
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       = 35 (swi4: clock sio)
trap number           = 12
panic: page fault
Ensure your kernel has at least "device pf", "device pfsyc", and "device plip".  Boot to the default mode.  Ensure the plip device has NO IP configuration (this MAY still occur when it does have an IP configuration, but I have not yet tested this).  Log in.  Run the following command as root: `ifconfig pfsync0 syncdev plip0` (substituting in other device numbers if necessary).

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