Not sure what triggered it, but it seems file system related. The second core dump didn't save because I forgot to move the dumpdir to /usr, it was something to do with ffs also though. GNU gdb 4.18 (FreeBSD) Copyright 1998 Free Software Foundation, Inc. GDB is free software, covered by the GNU General Public License, and you are welcome to change it and/or distribute copies of it under certain conditions. Type "show copying" to see the conditions. There is absolutely no warranty for GDB. Type "show warranty" for details. This GDB was configured as "i386-unknown-freebsd"...Deprecated bfd_read called at /usr/src/gnu/usr.bin/binutils/gdb/../../../../contrib/gdb/gdb/dbxread.c line 2627 in elfstab_build_psymtabs Deprecated bfd_read called at /usr/src/gnu/usr.bin/binutils/gdb/../../../../contrib/gdb/gdb/dbxread.c line 933 in fill_symbuf IdlePTD at physical address 0x003ab000 initial pcb at physical address 0x00306580 panicstr: ffs_blkfree: freeing free block panic messages: --- panic: ffs_blkfree: freeing free block syncing disks... 19 ad2: WRITE command timeout tag=0 serv=0 - resetting ata1: resetting devices .. done 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 giving up on 1 buffers Uptime: 25d22h35m26s dumping to dev #ad/0x20001, offset 790656 dump ata0: resetting devices .. done 125 124 123 122 121 120 119 118 117 116 115 114 113 112 111 110 109 108 107 106 105 104 103 102 101 100 99 98 97 96 95 94 93 92 91 90 89 88 87 86 85 84 83 82 81 80 79 78 77 76 75 74 73 72 71 70 69 68 67 66 65 64 63 62 61 60 59 58 57 56 55 54 53 52 51 50 49 48 47 46 45 44 43 42 41 40 39 38 37 36 35 34 33 32 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 69.82:1045 81.178.74.143:4666 in via fxp1 ad2: WRITE command timeout tag=0 serv=0 - resetting ata1: resetting devices .. done --- #0 dumpsys () at /usr/src/sys/kern/kern_shutdown.c:487 487 if (dumping++) { (kgdb) bt #0 dumpsys () at /usr/src/sys/kern/kern_shutdown.c:487 #1 0xc015ed08 in boot (howto=256) at /usr/src/sys/kern/kern_shutdown.c:316 #2 0xc015f13c in poweroff_wait (junk=0xc02c0620, howto=-1070856704) at /usr/src/sys/kern/kern_shutdown.c:595 #3 0xc022cf47 in ffs_blkfree (ip=0xc89f1e0c, bno=46208, size=16384) at /usr/src/sys/ufs/ffs/ffs_alloc.c:1450 #4 0xc023182e in handle_workitem_freeblocks (freeblks=0xc10dce80) at /usr/src/sys/ufs/ffs/ffs_softdep.c:2146 #5 0xc022fc1b in process_worklist_item (matchmnt=0x0, flags=0) at /usr/src/sys/ufs/ffs/ffs_softdep.c:723 #6 0xc022faaa in softdep_process_worklist (matchmnt=0x0) at /usr/src/sys/ufs/ffs/ffs_softdep.c:622 #7 0xc018e563 in sched_sync () at /usr/src/sys/kern/vfs_subr.c:1198 (kgdb) FreeBSD bone.bone.servebeer.com 4.10-STABLE FreeBSD 4.10-STABLE #0: Mon Oct 25 04:30:06 BST 2004 mrboo@bone2.bone.servebeer.com:/usr/obj/usr/src/sys/BONE i386 This one happened while I was asleep. It failed to fsck ad2 afterwards, so it was sat in single user mode. The second panic ALSO failed to fsck ad2 and sat in single user mode until I ran it manually. ad2 is actually a laptop drive. Perhaps this is a sign the disk is on it's way out? If that was the case I thought it would have just gone to click of death mode and the system would have locked up? Any help much appreciated. I am currently trying to update to the latest STABLE. In fact, the second panic happened during the first attempt at a make buildworld... this time around it's still running though.