(please CC as I'm not subscribed) Not sure if freebsd-stable@ is the correct list as this is 5.1-RELEASE-p2. Seems to have started after rebuild for -p2 patches. The box was quite stable before then. This is very easy to reproduce. It happens daily just before 24 hrs uptime. FreeBSD edge.internal 5.1-RELEASE-p2 FreeBSD 5.1-RELEASE-p2 #0: Sat Aug 30 13:07:49 CDT 2003 bweisz@edge.internal:/usr/obj/usr/src/sys/TESTBED i386 Fatal trap 12: page fault while in kernel mode fault virtual address = 0x71e51224 fault code = supervisor read, page not present instruction pointer = 0x8:0xc03809e7 stack pointer = 0x10:0xd8e28b28 frame pointer = 0x10:0xd8e28b80 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 = 560 (rtadvd) kernel: type 12 trap, code=0 Stopped at sysctl_iflist+0x197: movzwl 0x24(%eax),%eax db> trace sysctl_iflist(0,d8e28b98,e,51d600,98) at sysctl_iflist+0x197 sysctl_rtsock(c054db20,d8e28cb0,4,d8e28c0c,d8e28c0c) at sysctl_rtsock+0x111 sysctl_root(0,d8e28ca8,6,d8e28c0c,c150e390) at sysctl_root+0x12a userland_sysctl(c150e390,d8e28ca8,6,0,bfbffa9c) at userland_sysctl+0x14d __sysctl(c150e390,d8e28d10,c050a6b5,3fb,6) at __sysctl+0xb0 syscall(bfbf002f,bfbf002f,bfbf002f,0,bfbffa9c) at syscall+0x24e Xint0x80_syscall() at Xint0x80_syscall+0x1d --- syscall (202, FreeBSD ELF32, __sysctl), eip = 0x280be943, esp 0xbfbff9ec, ebp = 0xbfbffa18 --- db> panic panic: from debugger Debugger("panic") Fatal trap 3: breakpoint instruction fault while in kernel mode instruction pointer = 0x8:0xc047eb34 stack pointer = 0x10:0xd8e288a8 frame pointer = 0x10:0xd8e288b4 code segment = base 0x0, limit 0xfffff, type 0x1b = DPL 0, pres 1, def32 1, gran 1 processor eflags = IOPL = 0 current process = 560 (rtadvd) Stopped at sysctl_iflist+0x197: movzwl 0x24(%eax),%eax db> trace sysctl_iflist(0,d8e28b98,e,51d600,98) at sysctl_iflist+0x197 sysctl_rtsock(c054db20,d8e28cb0,4,d8e28c0c,d8e28c0c) at sysctl_rtsock+0x111 sysctl_root(0,d8e28ca8,6,d8e28c0c,c150e390) at sysctl_root+0x12a userland_sysctl(c150e390,d8e28ca8,6,0,bfbffa9c) at userland_sysctl+0x14d __sysctl(c150e390,d8e28d10,c050a6b5,3fb,6) at __sysctl+0xb0 syscall(bfbf002f,bfbf002f,bfbf002f,0,bfbffa9c) at syscall+0x24e Xint0x80_syscall() at Xint0x80_syscall+0x1d --- syscall (202, FreeBSD ELF32, __sysctl), eip = 0x280be943, esp 0xbfbff9ec, ebp = 0xbfbffa18 --- db> panic panic: from debugger Uptime: 23h53m18s