dtrace ustack kernel panic

[maestro something]

Hi,

when using the ustack action on the latest FreeBSD8.2 i386 the kernel
panics.

Here is the information I could gather:

let me know if I can provide more information. (i.e., i have the full crash
information 80+mbs handy)

Here is the backtrace:

Fatal trap 12: page fault while in kernel mode
cpuid = 0; apic id = 00
fault virtual address   = 0x108
fault code              = supervisor write, page not present
instruction pointer     = 0x20:0xc11012d7
stack pointer           = 0x28:0xcd3ed9f4
frame pointer           = 0x28:0xcd3eda0c
code segment            = base 0x0, limit 0xfffff, type 0x1b
                        = DPL 0, pres 1, def32 1, gran 1
processor eflags        = resume, IOPL = 0
current process         = 1132 (nc)
trap number             = 12
panic: page fault
cpuid = 0
KDB: stack backtrace:
#0 0xc09036a7 at kdb_backtrace+0x47
#1 0xc08d1a07 at panic+0x117
#2 0xc0c158c3 at trap_fatal+0x323
#3 0xc0c15bc0 at trap_pfault+0x2f0
#4 0xc0c1612a at trap+0x48a
#5 0xc0bfc97c at calltrap+0x6
#6 0xc10e992b at dtrace_panic+0x1b
#7 0xc10e995d at dtrace_assfail+0x2d
#8 0xc10fb28c at dtrace_probe+0x135c
#9 0xc1237f72 at systrace_probe+0x62
#10 0xc090f63f at syscallenter+0x47f
#11 0xc0c15c14 at syscall+0x34
#12 0xc0bfca11 at Xint0x80_syscall+0x21
Uptime: 3m0s
Physical memory: 239 MB
Dumping 79 MB: 64 48 32 16


Steps To reproduce:

the dtrace program (i.e., test.d) was:

#!/usr/sbin/dtrace -s

syscall::accept:return
/ execname == "nc" /
{
    printf("%s accept:return\n", execname);
    ustack();
}

% dtrace -s test.d

then running
% nc -vl 8080
on one shell and
% nc localhost 8080
on another would make the kernel panic

thanks
--m
-------------- next part --------------
A non-text attachment was scrubbed...
Name: core.txt.0
Type: application/octet-stream
Size: 65864 bytes
Desc: not available
Url : http://lists.freebsd.org/pipermail/freebsd-stable/attachments/20110726/997a7721/core.txt-0001.obj
-------------- next part --------------
A non-text attachment was scrubbed...
Name: info.0
Type: application/octet-stream
Size: 423 bytes
Desc: not available
Url : http://lists.freebsd.org/pipermail/freebsd-stable/attachments/20110726/997a7721/info-0001.obj