Date: Tue, 26 Jul 2011 14:05:04 +0300 From: Andriy Gapon <avg@FreeBSD.org> To: maestro something <maestro82@gmail.com> Cc: freebsd-stable@FreeBSD.org Subject: Re: dtrace ustack kernel panic Message-ID: <4E2E9F60.1060808@FreeBSD.org> In-Reply-To: <CAJ_JOqvEmXBTBABhUcJ66=bh9%2B8S%2BC9v30hXxVZiCXuEpGPJ1A@mail.gmail.com> References: <CAJ_JOqvEmXBTBABhUcJ66=bh9%2B8S%2BC9v30hXxVZiCXuEpGPJ1A@mail.gmail.com>
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on 26/07/2011 04:20 maestro something said the following:
> 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)
Use kgdb on the crash dump, go to the dtrace_probe frame and see which exactly
assert fails and why.
> 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
--
Andriy Gapon
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