DTrace panic

[Bjoern A. Zeeb]

Hi,

I am seeing this panic when trying to use DTrace on r299073.   I
cannot rule out that it's my (experimental) environment;  just wanted
to check if it might have been a known breakage before digging into it.

# dtrace -n 'dtrace:::BEGIN { printf("Hello FreeBSD!\n"); }'
dtrace -n 'dtrace:::BEGIN { printf("Hello FreeBSD!\n"); }'
dtrace: description 'dtrace:::BEGIN ' matched 1 probe
kernel trap 12 with interrupts disabled


Fatal trap 12: page fault while in kernel mode
fault virtual address   = 0xae
fault code              = supervisor read data, page not present
instruction pointer     = 0x20:0xfffff800012ebc03
stack pointer           = 0x28:0xfffffe0000226740
frame pointer           = 0x28:0xfffffe0000226780
code segment            = base 0x0, limit 0xfffff, type 0x1b
                         = DPL 0, pres 1, long 1, def32 0, gran 1
processor eflags        = IOPL = 0
current process         = 576 (dtrace)
[ thread pid 576 tid 100048 ]
Stopped at      0xfffff800012ebc03:     addl    %eax,(%rax)
db> where
where
Tracing pid 576 tid 100048 td 0xfffff80001f0f000
dmapbase() at 0xfffff800012ebc03/frame 0xfffffe0000226780
dtrace_xcall() at dtrace_xcall+0xb2/frame 0xfffffe00002267d0
dtrace_fuword32() at dtrace_fuword32+0xfd66/frame 0xfffffe0000226830
dtrace_fuword32() at dtrace_fuword32+0xa6ec/frame 0xfffffe0000226930
dev2udev() at dev2udev+0x37ef/frame 0xfffffe0000226990
kern_ioctl() at kern_ioctl+0x1a7/frame 0xfffffe0000226a00
sys_ioctl() at sys_ioctl+0x171/frame 0xfffffe0000226ad0
amd64_syscall() at amd64_syscall+0x4c6/frame 0xfffffe0000226bf0
Xfast_syscall() at Xfast_syscall+0xfb/frame 0xfffffe0000226bf0
--- syscall (54, FreeBSD ELF64, sys_ioctl), rip = 0x80125267a, rsp = 0x7fffffffe9c8, rbp = 0x7fffffffea10 ---

db> show reg
show reg
cs                        0x20
ds                        0x3b
es                        0x3b
fs                        0x13
gs                        0x1b
ss                        0x28
rax                       0xae
rcx                          0
rdx         0xfffffe0000817000
rbx         0xffffffff802b43f0
rsp         0xfffffe0000226758
rbp         0xfffffe0000226780
rsi         0xffffffff802b43f0
rdi         0xfffff800012ebc00
r8          0xfffff800012ebc00
r9          0xfffff800012ebc00
r10         0xfffff800012ebc00
r11         0xfffffe00002266f8
r12         0xffffffff80429f30  smp_no_rendevous_barrier
r13         0xfffffe0001127000
r14         0xfffff800012ebc00
  -More--
r15         0xfffff800012ebc00
rip         0xfffff800012ebc03
rflags                    0xae
0xfffff800012ebc03:     addl    %eax,(%rax)