[ktap] Re: KTAP

  • From: "zhangwei(Jovi)" <jovi.zhangwei@xxxxxxxxxx>
  • To: <ktap@xxxxxxxxxxxxx>
  • Date: Thu, 23 May 2013 18:39:29 +0800

On 2013/5/23 17:36, Oded Gabbay wrote:
> On 23/05/13 12:13, zhangwei(Jovi) wrote:
>> On 2013/5/23 16:48, Oded Gabbay wrote:
>>> Hi Jovi,
>>>
>>> I read today about the ktap release in LWN and tried to give it a go on my 
>>> custom board, which contains a powerpc processor from Freescale called 
>>> P2020 (e500v2 core).
>>>
>>> I have two comments and a question:
>>>
>>> 1. I needed to enable CONFIG_RELAY in the kernel configuration, although 
>>> this is not mentioned in the requirements. Maybe you should add it.
>>>
>> Involve ktap mailing list :)
>>
>> Thanks, you are right, I will add it.
>>
>>> 2. I needed to add #include <linux/vmalloc.h> to ktap.c for compilation
>>>
>> which kernel version of the board? currently ktap can support kernel 3.1 or 
>> later, older kernel need some patch to run ktap.
>> I haven't compile ktap in powerpc, so might you are right.
> My kernel version is 3.4.41.
>>
>>> I now arrived to a situation where I insmod the ktapvm.ko on my board, but 
>>> when I run:
>>> ./ktap scripts/syscalls.kp
>>>
>>> I get the following error:
>>> open /sys/kernel/debug/ktap/ktapvm failed: No such file or directory
>>>
>>> I checked and indeed there is no /sys/kernel/debug/ktap folder (debug 
>>> folder is empty).
>> I guess you are missing mount debugfs?
>>
>> mount -t debugfs none /sys/kernel/debug/
>>
>> Also I will add this into ktap doc.
> Yes, I was missing the mount. Thanks :)
>> Note that currently ktap is not stable enough to running in production 
>> system, but I'm trying to make it more stable :)
> I'm aware of that and I'm not putting it in production, but thanks for the 
> warning.
> After I fixed the mount issue, I was able to run the syscalls script but the 
> kernel immediately crashed...
> I will try to look into it.
> This was the message from the kernel:
> 
> [cj:/usr/local/ktap] # ./ktap scripts/syscalls.kp
> Unable to handle kernel paging request for data at address 0x00000000
> Faulting instruction address: 0xf1eb5dcc
> Oops: Kernel access of bad area, sig: 11 [#1]
> PREEMPT SMP NR_CPUS=2 P2020 FSP150
> Modules linked in: ktapvm(O) mdio(O) hardware_version(PO) clipresent(PO) 
> monotonic(O) restartcause(PO) panic_buffer(O) [last unloaded: ktapvm]
> NIP: f1eb5dcc LR: f1eb5d90 CTR: c0265f04
> REGS: eedd5c90 TRAP: 0300   Tainted: P           O 
> (3.4.41-dev_ogabbay-105684*)
> MSR: 00029000 <CE,EE,ME>  CR: 44000482  XER: 20000000
> DEAR: 00000000, ESR: 00000000
> TASK = ef0c6820[2097] 'ktap' THREAD: eedd4000 CPU: 1
> GPR00: 00000000 eedd5d40 ef0c6820 eedd5d4c f1eb801c 00000016 eedd5d6a 0000003a
> GPR08: eedd5d54 00000000 00000000 f1eb801d c0265f04 1002cacc 00000005 00000003
> GPR16: 00000001 eede9628 00000001 eede9600 00000000 eee6e640 00000000 00000000
> GPR24: 00000000 eedd5d4c f1ec0000 eede9200 ffffffff eede8600 eedd5d4c eedd5db8
> NIP [f1eb5dcc] ftrace_on_event_call.clone.6+0xb4/0x1fc [ktapvm]
> LR [f1eb5d90] ftrace_on_event_call.clone.6+0x78/0x1fc [ktapvm]
> Call Trace:
> [eedd5d40] [f1eb0824] kp_tstring_newlstr+0xdc/0x164 [ktapvm] (unreliable)
> [eedd5db0] [f1eb5ff4] ktap_lib_probe+0xe0/0x198 [ktapvm]
> [eedd5de0] [f1eb2a90] precall+0x1e4/0x318 [ktapvm]
> [eedd5e00] [f1eb3244] kp_call+0x680/0x1180 [ktapvm]
> [eedd5e60] [f1eaf2c0] ktap_ioctl+0x20c/0x30c [ktapvm]
> [eedd5ea0] [c010d4f4] do_vfs_ioctl+0xa0/0x754
> [eedd5f10] [c010dc44] sys_ioctl+0x9c/0xa4
> [eedd5f40] [c000f3a0] ret_from_syscall+0x0/0x3c
> --- Exception: c01 at 0xff1e254
>     LR = 0xffb2c0c
> Instruction dump:
> 419e0024 88030000 2f800000 409e0148 88180000 2f800000 409e011c 3b200000
> 3b000000 3f40f1ec 3ac00000 813a93a0 <83c90000> 7f89f000 419e00c0 3b5a93a0
> ---[ end trace b87e7dec14e55ffe ]---
> 
> cannot lookup ftrace_events in kallsyms
> Kernel panic - not syncing: Fatal exception
> Rebooting in 5 seconds..

Please pull latest ktap from github, I just figure out I missed function return 
value check.
Then there will have no panic, I assume.

But I'm still curious on why your kernel didn't exported "ftrace_events", 
CONFIG_KALLSYMS not enabled?

> 
>>
>> Thanks.
>>> I thought maybe you would have any idea how to fix this and save me time.
>>>
>>> -- 
>>> Best regards,
>>> Oded Gabbay
>>> Principal Engineer Advanced Packet Technologies
>>> ADVA Optical Networking Israel Ltd.
>>> P.O. Box 2552
>>> 2 Hatidhar St.
>>> Raanana 43665, Israel
>>> Tel: +(972)-9-7750130
>>> Fax: +(972)-9-7462092
>>> Mobile: +(972)-54-6543998
>>> E-mail: ogabbay@xxxxxxxxxxxxxxx <mailto:ogabbay@xxxxxxxxxxxxxxx>
>>>   www.advaoptical.com <http://www.advaoptical.com>
>>> *Let's ADVANCE*
>>>   ADVA Optical Networking SE is a European stock corporation ("Societas 
>>> Europaea") with registered offices at Maerzenquelle 1-3, D-98617 Meiningen, 
>>> Germany * CEO: Brian L. Protiva, Chief Officers: Dr.
>>> Christoph Glingener, Christian Unterberger, Jaswir Singh * Chairman of the 
>>> Supervisory Board: Anthony Maher * AG Jena HRB 508155 * VAT No. DE 175 446 
>>> 349
>>
> 
> 
> 
> .
> 



Other related posts: