Re: DTrace panic while probing syscall::open (and possibly many others)

on 18/06/2009 12:43 Thomas Backman said the following:
> #10 0xffffffff816c9140 in vpanic_common () from /boot/kernel/dtrace.ko
> #11 0xffffffff816b3067 in dtrace_panic (format=Variable "format" is not
> available.
> )
>     at
> /usr/src/sys/modules/dtrace/dtrace/../../../cddl/contrib/opensolaris/uts/common/dtrace/dtrace.c:600
> 
> #12 0xffffffff816b309d in dtrace_assfail (
>     a=0xffffffff816d4b88 "kaddr >= kernelbase && kaddr + size >= kaddr",
>     f=0xffffff803e770370
> "ÀàF\201ÿÿÿÿÀàF\201ÿÿÿÿ0\005w>\200ÿÿÿÇà\206\200ÿÿÿÿWD\210\200ÿÿÿÿ`&t~",
> l=Variable "l" is not available.
> )
>     at
> /usr/src/sys/modules/dtrace/dtrace/../../../cddl/contrib/opensolaris/uts/common/dtrace/dtrace.c:607
> 
> #13 0xffffffff816b3140 in dtrace_copycheck (uaddr=34365163021,
> kaddr=Variable "kaddr" is not available.
> )
>     at dtrace_isa.c:527
> #14 0xffffffff816b31fc in dtrace_copyinstr (uaddr=34365163021,
>     kaddr=18446743524025463312, size=256, flags=0xffffffff8146e0c0)
>     at dtrace_isa.c:558


kaddr=18446743524025463312 == FFFFFF8004467210
I think kernelbase on amd64 is 0xFFFFFFFF80000000.
FFFFFF8004467210 kaddr
is smaller than
FFFFFFFF80000000 kernelbase

The numbers do look suspiciously similar, so I am not sure if you are seeing a
race or a real bug somewhere.

> #15 0xffffffff816c10f1 in dtrace_dif_emulate (difo=0xffffffff80884457,
>     mstate=0xffffff803e770a10, vstate=0xffffff0002930c38,
>     state=0xffffff0002930c00)
>     at
> /usr/src/sys/modules/dtrace/dtrace/../../../cddl/contrib/opensolaris/uts/common/dtrace/dtrace.c:3452
> 
> #16 0xffffffff816c233a in dtrace_probe (id=Variable "id" is not available.
> )
>     at
> /usr/src/sys/modules/dtrace/dtrace/../../../cddl/contrib/opensolaris/uts/common/dtrace/dtrace.c:6226
> 
> #17 0xffffffff817f2145 in systrace_probe () from /boot/kernel/systrace.ko
> #18 0xffffffff80887c7d in syscall (frame=0xffffff803e770c90)
>     at /usr/src/sys/amd64/amd64/trap.c:997
> #19 0xffffffff8086e350 in Xfast_syscall ()
>     at /usr/src/sys/amd64/amd64/exception.S:364
> #20 0x000000080050c3ac in ?? ()


-- 
Andriy Gapon