Re: LOR/page fault panic vfs_mountroot

On Wed, Apr 20, 2005 at 01:04:08PM -0700, othermark wrote:
> Current as of a few minutes ago.  LOR/panic.  Dual processor box.
> 
> kernel has vlan, ipfw, and dummynet enabled, but this doesn't
> look like the problem.  
> 
> Curiously, booting single user and mounting root there doesn't 
> panic, but it does panic if you try to 'exit' to multiuser.
> 
> [...]
> Timecounters tick every 1.000 msec
> ipfw2 (+ipv6) initialized, divert loadable, rule-based forwarding disabled,
> default to accept, logging disabled
> ad0: 19092MB <WDC WD200EB-32CSF0 04.01B04> at ata0-master UDMA33
> acd0: CDROM <TOSHIBA CD-ROM XM-6702B/1007> at ata1-master UDMA33
> ATA PseudoRAID loaded
> SMP: AP CPU #1 Launched!
> Trying to mount root from ufs:/dev/ad0s1a
> lock order reversal
>  1st 0xc0a2d740 vm page queue mutex (vm page queue mutex)
> _at_ /usr/src/sys/kern/vfs_bio.c:1485
>  2nd 0xc25e4d6c vnode interlock (vnode interlock)
> _at_ /usr/src/sys/kern/vfs_subr.c:1992

This has been reported a half-dozen times or so.

> Fatal trap 12: page fault while in kernel mode
> cpuid = 0; apic id = 01
> fault virtual address   = 0x4ac0c092
> fault code              = supervisor read, page not present
> instruction pointer     = 0x20:0xc0703f88
> stack pointer           = 0x28:0xe5092b78
> frame pointer           = 0x28:0xe5092b78
> 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         = 73 (sysctl)
> [thread pid 73 tid 100060 ]
> Stopped at      strlen+0x8:     cmpb    $0,0(%edx)
> db> show alllocks
> Process 73 (sysctl) thread 0xc23b2600 (100060)
> exclusive sx sysctl lock r = 0 (0xc09d1c60) locked
> _at_ /usr/src/sys/kern/kern_sysctl.c:1335
> exclusive sleep mutex Giant r = 0 (0xc09d1620) locked
> _at_ /usr/src/sys/kern/kern_sysctl.c:1273

I think this one might be new.  Please obtain a debugging traceback.

Kris