Kernel crash during heavy disk access

I experienced kernel crashes while make world or ports.
For example:
# cd /usr/port/lang/mono
# make

Will cause the crash, from /var/crash/core.txt:
eb8460p dumped core - see /var/crash/vmcore.5

Mon Jul  8 21:22:58 PDT 2013

FreeBSD eb8460p 10.0-CURRENT FreeBSD 10.0-CURRENT #5 r253048: Mon Jul  8
19:07:18 PDT 2013     root_at_eb8460p:/u
sr/obj/usr/src/sys/EB8460p  amd64

panic: ffs_valloc: dup alloc

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Unread portion of the kernel message buffer:
mode = 0100600, inum = 52969060, fs = /
panic: ffs_valloc: dup alloc
cpuid = 0
KDB: stack backtrace:
#0 0xffffffff805fd6d0 at kdb_backtrace+0x60
#1 0xffffffff805c5b65 at panic+0x155
#2 0xffffffff807dda6a at ffs_valloc+0x88a
#3 0xffffffff8081a34c at ufs_makeinode+0x7c
#4 0xffffffff808d2872 at VOP_CREATE_APV+0x92
#5 0xffffffff80670c49 at vn_open_cred+0x2c9
#6 0xffffffff8066a22f at kern_openat+0x1ef
#7 0xffffffff8085db47 at amd64_syscall+0x357
#8 0xffffffff808475db at Xfast_syscall+0xfb
Uptime: 6m57s
Dumping 599 out of 3972
MB:..3%..11%..22%..33%..41%..51%..62%..73%..81%..91%

Reading symbols from /boot/modules/cuse4bsd.ko...done.
Loaded symbols for /boot/modules/cuse4bsd.ko
Reading symbols from /boot/kernel/fdescfs.ko.symbols...done.
Loaded symbols for /boot/kernel/fdescfs.ko.symbols
Reading symbols from /boot/kernel/ng_ubt.ko.symbols...done.
Loaded symbols for /boot/kernel/ng_ubt.ko.symbols
Reading symbols from /boot/kernel/netgraph.ko.symbols...done.
Loaded symbols for /boot/kernel/netgraph.ko.symbols
Reading symbols from /boot/kernel/ng_hci.ko.symbols...done.
Loaded symbols for /boot/kernel/ng_hci.ko.symbols
Reading symbols from /boot/kernel/ng_bluetooth.ko.symbols...done.
Loaded symbols for /boot/kernel/ng_bluetooth.ko.symbols
Reading symbols from /boot/kernel/ums.ko.symbols...done.
Loaded symbols for /boot/kernel/ums.ko.symbols
Reading symbols from /boot/kernel/ng_l2cap.ko.symbols...done.
Loaded symbols for /boot/kernel/ng_l2cap.ko.symbols
Reading symbols from /boot/kernel/ng_btsocket.ko.symbols...done.
Loaded symbols for /boot/kernel/ng_btsocket.ko.symbols
Reading symbols from /boot/kernel/ng_socket.ko.symbols...done.
Loaded symbols for /boot/kernel/ng_socket.ko.symbols
#0  doadump (textdump=<value optimized out>) at pcpu.h:236
236     pcpu.h: No such file or directory.
        in pcpu.h
(kgdb) #0  doadump (textdump=<value optimized out>) at pcpu.h:236
#1  0xffffffff805c57e0 in kern_reboot (howto=260)
    at /usr/src/sys/kern/kern_shutdown.c:447
#2  0xffffffff805c5ba4 in panic (fmt=<value optimized out>)
    at /usr/src/sys/kern/kern_shutdown.c:754
#3  0xffffffff807dda6a in ffs_valloc (pvp=<value optimized out>,
    mode=<value optimized out>, cred=<value optimized out>,
    vpp=<value optimized out>) at /usr/src/sys/ufs/ffs/ffs_alloc.c:1022
#4  0xffffffff8081a34c in ufs_makeinode (mode=<value optimized out>,
    dvp=0xfffffe011bf44ce8, vpp=0xffffff811ba058d8,
cnp=0xffffff811ba05900)
    at /usr/src/sys/ufs/ufs/ufs_vnops.c:2620
#5  0xffffffff808d2872 in VOP_CREATE_APV (vop=<value optimized out>,
    a=<value optimized out>) at vnode_if.c:265
#6  0xffffffff80670c49 in vn_open_cred (ndp=0xffffff811ba05880,
    flagp=0xffffff811ba0595c, cmode=420, vn_open_flags=<value optimized
out>,
    cred=0xfffffe0011fcee00, fp=0xfffffe00110925a0) at vnode_if.h:109
#7  0xffffffff8066a22f in kern_openat (td=0xfffffe011960f920,
    fd=<value optimized out>,
    path=0x801dbd580 <Address 0x801dbd580 out of bounds>,
    pathseg=UIO_USERSPACE, flags=1538, mode=<value optimized out>)
    at /usr/src/sys/kern/vfs_syscalls.c:1093
#8  0xffffffff8085db47 in amd64_syscall (td=0xfffffe011960f920,
traced=0)
    at subr_syscall.c:134
#9  0xffffffff808475db in Xfast_syscall ()
    at /usr/src/sys/amd64/amd64/exception.S:391
#10 0x00000008013a5f2a in ?? ()
Previous frame inner to this frame (corrupt stack?)
Current language:  auto; currently minimal
(kgdb)


-- 
Eric Camachat