Bug 30495

Unfortunately the machine crashed when I wasn't around, but it would have
been doing very little other than packet forwarding via user-ppp and
pppoa2m. I do, however have a crash dump, which says:

fanf@hand.dotat.at:~
:; gdb -k /boot/SHARP/kernel.debug /var/crash/vmcore.2
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This GDB was configured as "i386-unknown-freebsd"...
IdlePTD 4132864
initial pcb at 347980
panicstr: from debugger
panic messages:
---
Fatal trap 12: page fault while in kernel mode
fault virtual address   = 0x4521007c
fault code              = supervisor read, page not present
instruction pointer     = 0x8:0xc015a1ad
stack pointer           = 0x10:0xcb6e1868
frame pointer           = 0x10:0xcb6e1890
code segment            = base rx0, limit 0xfffff, type 0x1b
                        = DPL 0, pres 1, def32 1, gran 1
processor eflags        = interrupt enabled, resume, IOPL = 0
current process         = 4615 (pppoa2m)
interrupt mask          = net tty bio cam
panic: from debugger
panic: from debugger
Uptime: 1d6h35m45s
dumping to dev #ad/0x20001, offset 766144
dump ata0: resetting devices .. ata0: mask=01 ostat0=50 ostat2=00
ata0-master: ATAPI probe a=00 b=00
ata0-slave: ATAPI probe a=00 b=00
ata0: mask=01 status0=50 status1=00
ata0-master: ATA probe a=01 b=a5
ata0: devices=01
ata0-master: success setting PIO4 on generic chip
done
127 126 125 124 123 122 121 120 119 118 117 116 115 114 113 112 111 110 109 108
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 3
0 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
---
#0  dumpsys () at /FreeBSD/releng4/sys/kern/kern_shutdown.c:473
473             if (dumping++) {
(kgdb) bt
#0  dumpsys () at /FreeBSD/releng4/sys/kern/kern_shutdown.c:473
#1  0xc015eaa8 in boot (howto=260)
    at /FreeBSD/releng4/sys/kern/kern_shutdown.c:313
#2  0xc015ee9d in panic (fmt=0xc02c86a4 "from debugger")
    at /FreeBSD/releng4/sys/kern/kern_shutdown.c:581
#3  0xc0139b19 in db_panic (addr=-1072324179, have_addr=0, count=-1,
    modif=0xcb6e16d4 "") at /FreeBSD/releng4/sys/ddb/db_command.c:435
#4  0xc0139ab7 in db_command (last_cmdp=0xc0308a04, cmd_table=0xc0308844,
    aux_cmd_tablep=0xc03426f8) at /FreeBSD/releng4/sys/ddb/db_command.c:333
#5  0xc0139b7e in db_command_loop ()
    at /FreeBSD/releng4/sys/ddb/db_command.c:457
#6  0xc013bd37 in db_trap (type=12, code=0)
    at /FreeBSD/releng4/sys/ddb/db_trap.c:71
#7  0xc02a38ce in kdb_trap (type=12, code=0, regs=0xcb6e1828)
    at /FreeBSD/releng4/sys/i386/i386/db_interface.c:158
#8  0xc02b11fc in trap_fatal (frame=0xcb6e1828, eva=1159790716)
    at /FreeBSD/releng4/sys/i386/i386/trap.c:951
#9  0xc02b0ec5 in trap_pfault (frame=0xcb6e1828, usermode=0, eva=1159790716)
    at /FreeBSD/releng4/sys/i386/i386/trap.c:849
#10 0xc02b0a63 in trap (frame={tf_fs = 16, tf_es = -881983472,
      tf_ds = -881983472, tf_edi = -1048069120, tf_esi = -1070476896,
      tf_ebp = -881977200, tf_isp = -881977260, tf_ebx = -1048069120,
      tf_edx = -1070304376, tf_ecx = 10, tf_eax = 1159790680, tf_trapno = 12,
      tf_err = 0, tf_eip = -1072324179, tf_cs = 8, tf_eflags = 66182,
      tf_esp = -1051797572, tf_ss = 1024})
    at /FreeBSD/releng4/sys/i386/i386/trap.c:448
#11 0xc015a1ad in malloc (size=1024, type=0xc031d1a0, flags=1)
    at /FreeBSD/releng4/sys/kern/kern_malloc.c:237
#12 0xc0242fa7 in uhci_allocm (bus=0xc14ec000, dma=0xc14ed7bc, size=1024)
    at /FreeBSD/releng4/sys/dev/usb/uhci.c:493
#13 0xc02462da in usbd_transfer (xfer=0xc14ed780)
    at /FreeBSD/releng4/sys/dev/usb/usbdi.c:274
#14 0xc024770a in usbd_bulk_transfer (xfer=0xc14ed780, pipe=0xc1869680,
    flags=4, timeout=1000, buf=0xcb6e19b8, size=0xcb6e1934,
    lbl=0xc02ea1d5 "ugenrb") at /FreeBSD/releng4/sys/dev/usb/usbdi_util.c:511
#15 0xc024a2fa in ugen_do_read (sc=0xc074b000, endpt=7, uio=0xcb6e1ed8,
    flag=8323072) at /FreeBSD/releng4/sys/dev/usb/ugen.c:580
#16 0xc024a4af in ugenread (dev=0xc15cd480, uio=0xcb6e1ed8, flag=8323072)
    at /FreeBSD/releng4/sys/dev/usb/ugen.c:656
#17 0xc0199b26 in spec_read (ap=0xcb6e1e6c)
    at /FreeBSD/releng4/sys/miscfs/specfs/spec_vnops.c:253
#18 0xc02326a4 in ufsspec_read (ap=0xcb6e1e6c)
    at /FreeBSD/releng4/sys/ufs/ufs/ufs_vnops.c:1843
#19 0xc0232d31 in ufs_vnoperatespec (ap=0xcb6e1e6c)
    at /FreeBSD/releng4/sys/ufs/ufs/ufs_vnops.c:2400
#20 0xc019511c in vn_read (fp=0xc18e3300, uio=0xcb6e1ed8, cred=0xc161b080,
    flags=0, p=0xcb5fbd40) at vnode_if.h:334
#21 0xc016d9cb in dofileread (p=0xcb5fbd40, fp=0xc18e3300, fd=6,
    buf=0xbfbfed90, nbyte=3392, offset=-1, flags=0)
---Type <return> to continue, or q <return> to quit---
    at /FreeBSD/releng4/sys/sys/file.h:146
#22 0xc016d88f in read (p=0xcb5fbd40, uap=0xcb6e1f80)
    at /FreeBSD/releng4/sys/kern/sys_generic.c:117
#23 0xc02b14e9 in syscall2 (frame={tf_fs = -1078001617, tf_es = -1078001617,
      tf_ds = -1078001617, tf_edi = -1077937260, tf_esi = -1077937292,
      tf_ebp = -1077940896, tf_isp = -881975340, tf_ebx = 7, tf_edx = 6,
      tf_ecx = 60, tf_eax = 3, tf_trapno = 7, tf_err = 2, tf_eip = 1208884752,
      tf_cs = 31, tf_eflags = 663, tf_esp = -1077940940, tf_ss = 47})
    at /FreeBSD/releng4/sys/i386/i386/trap.c:1155
#24 0xc02a46c5 in Xint0x80_syscall ()
#25 0x80499bf in ?? ()
#26 0x804a3d0 in ?? ()
#27 0x8048ba9 in ?? ()
(kgdb)