Fatal trap 12



  • Fresh install of PFsense ad within 24 hrs I got a crash dump message:

    Fatal trap 12: page fault while in kernel mode
    cpuid = 3; apic id = 03
    fault virtual address = 0x20000018
    fault code = supervisor write data, page not present
    instruction pointer = 0x20:0xffffffff80e188c2
    stack pointer         = 0x28:0xfffffe00f9ef3380
    frame pointer         = 0x28:0xfffffe00f9ef3410
    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 = 43408 (sh)

    The part that says 'page not present' would this be a page in memory?
    Any way I need a pointer as to where to start troubleshooting.
    I have seen this before from the computer.
    Sometimes it will go for 2 weeks no problem.
    It ran for a year before this problem showed up.

    The hardware is:
    MSI AM1I motherboard
    AMD athlon 5350 cpu
    4Gb memory
    New Samsung SSD
    Intel dual port NIC - pcie x4



  • The part that says 'page not present' would this be a page in memory?
    A page that should be in memory. When the processor is switched to kernel mode to do privileged things, those things are generally expected to run quickly. To achieve that (and avoid other nasty possibilities) no page faults are allowed (a page fault means that the needed page would have to be read in to memory from storage). So it is expected that all pages referenced are already memory-resident.

    The problem is that the needed page is not already in memory - but in kernel mode the system refuses to wait for it to be read in.

    This should never happen. Almost by definition it is a bug in FreeBSD. Most often a timing interaction that only crops up intermittently.