Bug 26437

System is quite stable and handles concurrent tasks well until... 
it seems... the two processors start competing for disk resources
through either swapping or file access.  Under heavy loads the problem
occurs within 20 to 30 minutes.

Additional info is contained below....

u2# gdb -k kernel /usr/wrk/k1/vmcore.0
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This GDB was configured as "i386-unknown-freebsd"...
(no debugging symbols found)...
SMP 2 cpus
IdlePTD 3461120
initial pcb at 2bdae0
panicstr: non-maskable interrupt trap
panic messages:
---
Fatal trap 19: non-maskable interrupt trap while in kernel mode
mp_lock = 00000002; cpuid = 0; lapic.id = 00000000
instruction pointer     = 0x8:0xc018fcfc
stack pointer           = 0x10:0xc8840e3c
frame pointer           = 0x10:0xc8840e44
code segment            = base rx0, limit 0xfffff, type 0x1b
                        = DPL 0, pres 1, def32 1, gran 1
processor eflags        = interrupt enabled, IOPL = 0
current process         = 1136 (top)
interrupt mask          = none <- SMP: XXX
trap number             = 19
panic: non-maskable interrupt trap
mp_lock = 00000002; cpuid = 0; lapic.id = 00000000
boot() called on cpu#0

syncing disks... 1 1
done
Uptime: 10h3m40s

dumping to dev #da/0x20001, offset 270432
dump 128 127 126 125 124 123 122 121 120 119 118 117 116 115 114 113 112 111 110 109 108 107 106 105 104 103 102 101 100 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 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  0xc0158eae in dumpsys ()
(kgdb) where
#0  0xc0158eae in dumpsys ()
#1  0xc0158ccf in boot ()
#2  0xc0159080 in poweroff_wait ()
#3  0xc0257643 in trap_fatal ()
#4  0xc0256f93 in trap ()
#5  0xc018fcfc in spec_vnoperate ()
#6  0xc018c005 in vn_read ()
#7  0xc0166c40 in dofileread ()
#8  0xc0166b06 in read ()
#9  0xc025796d in syscall2 ()
#10 0xc024594b in Xint0x80_syscall ()
#11 0x280c946c in ?? ()
#12 0x280c96df in ?? ()
#13 0x280c96df in ?? ()
#14 0x280c96df in ?? ()
#15 0x280c96df in ?? ()
#16 0x280c9843 in ?? ()
#17 0x280c9416 in ?? ()
#18 0x804c195 in ?? ()
#19 0x804b745 in ?? ()
#20 0x804cecc in ?? ()
#21 0x8049471 in ?? ()
(kgdb) .... now what should I do??? I'm new at this :)

Fix: 

none known at this time.
How-To-Repeat: Either run bonnie and wait until the seekers start or
run a couple of programs that allocate a lot of memory to force
swapping and wait 20 to 30 minutes.