# kernel panic during reboot



## macfreek (Aug 24, 2012)

I just got a new server (ASRock E350M1/USB3 motherboard, 16 GByte memory) and installed FreeBSD 9.0-RELEASE. An issue I have is that I can't reboot. If I halt or reboot the machine (with `/sbin/reboot` or `/sbin/shutdown -r` or `-h`), the machine seems to shutdown properly at first, but by the time it should actually reboot, it displays the following kernel panic:


```
trap number             = 12
panic: page fault
cpuid = 0
uptime = 49s

Fatal trap 12: page fault while in kernel mode
cpuid = 0; apic id = 00
fault virtual address   = 0x0
fault code              = supervisor write data, page not present
instruction pointer     = 0x20:0xffffffff80b4026c
stack pointer           = 0x28:0xffffffff81178d70
frame pointer           = 0x28:0xffffffff81178d80
code segment            = base 0x0, limit 0xfffff, type 0x1b
                        = DPL 0, pres 1, long 1, def32 0, gran 1
processor eflags        = interrupt enabled, resume, IOPL = 0
current process         = 1627  (reboot)
trap number             = 12
panic: page fault
cpuid = 0
uptime = 49s

kernel trap 12 with interrupts disabled
```

The above numbers are the same each time. The only difference I see is that when I run `/sbin/shutdown`, the current process is 1 (init) instead of reboot.

Would you have any advice how to debug this?

So far, I tried playing with the ACPI (power saving) settings in the BIOS, in particular with these values:

 Suspend to RAM: auto
 RTC Alarm power on: by OS
 ACPI HPET table: disabled

The only change I saw is that instead of displaying gooblygook on screen, I now see the error message in plain ASCII.

During installation of FreeBSD, I choose not to install the lib32 packages. Could that be a cause?

I tried to see if I can debug some more by setting 
	
	



```
dumpdev="AUTO"
```
 in rc.conf, but dmesg had this warning "`no suitable dump device was found`", and I didn't find any memory dump.

Any advice how to proceed?

Edit 2014-08-28: Fix faulty BBCode.


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## SirDice (Aug 24, 2012)

Trap 12 is usually caused by bad hardware. Make sure your memory is still good and you don't have any bad sectors on the drive.


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## macfreek (Aug 25, 2012)

What does "trap 12" mean exactly? So far I have not seen any indication that there is a hardware failure. A short memtest turned up fine, I'm now running memtest86+ overnight. More importantly, the kernel panic is completely reproducible: it always happens during reboot and shutdown, and has never occurred otherwise. If it was a hardware issue, I expected less predictable behaviour.

I have a few options now. More hardware tests (I have not found a good SSD tester yet); getting the memory dump working to see in what code the error occurs; recompiling the kernel myself; or fiddling some more with ACPI settings. If memtest reports no errors, I guess I'll try the memory dump. But since I'm still completely in the dark here, all guidance is most appreciated.


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## macfreek (Aug 21, 2014)

I just upgraded to FreeBSD 9.3, and I'm happy to report that the kernel panic no longer occurs. So it was indeed a bug in FreeBSD, and not a hardware bug, as @SirDice suggested. Kudos to whoever fixed it.


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