Advanced Topics. Here is typical kernel panic: Fatal trap 12: page fault while in kernel mode fault virtual address = 0x40 fault code = supervisor read, page not present instruction pointer = 0x8:0xf014a7e5 stack pointer = 0x10:0xf4ed6f24 frame pointer = 0x10:0xf4ed6f28 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 = 80 (mount) interrupt mask = trap number = 12 panic: page fault When you see a message like this, it is not enough to just reproduce it and send it in.
The instruction pointer value is important; unfortunately, it is also configuration dependent. In other words, the value varies depending on the exact kernel image that you are using. If you are using a GENERIC kernel image from one of the snapshots, then it is possible for somebody else to track down the offending function, but if you are running a custom kernel then only you can tell us where the fault occurred.
Note: Tip: Architecture Handbook. Handbook. Man Pages: Index Page. FreeBSD Man Page Topics: A. FreeBSD Man Pages. Kernel initialization. Let us take a look at the command that links the kernel. This will help identify the exact location where the loader passes execution to the kernel. This location is the kernel's actual entry point. sys/conf/Makefile.i386: ld -elf -Bdynamic -T /usr/src/sys/conf/ldscript.i386 -export-dynamic \ -dynamic-linker /red/herring -o kernel -X locore.o \ <lots of kernel .o files> A few interesting things can be seen here. First, the kernel is an ELF dynamically linked binary, but the dynamic linker for kernel is /red/herring, which is definitely a bogus file.
Second, taking a look at the file sys/conf/ldscript.i386 gives an idea about what ld options are used when compiling a kernel. Sys/conf/ldscript.i386: ENTRY(btext) says that a kernel's entry point is the symbol `btext'. Sys/i386/i386/locore.s: .text /********************************************************************** * * This is where the bootblocks start us, set the ball rolling... * */ NON_GPROF_ENTRY(btext) Then, enabling paging: Pthreads Tutorial. The FreeBSD Project.