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List:       opensolaris-mdb-discuss
Subject:    Re: [mdb-discuss] MDB is not showing any parameters in stack back
From:       Tirthankar <Tirthankar.Das () Sun ! COM>
Date:       2007-07-13 14:33:05
Message-ID: 46978A51.4080802 () Sun ! COM
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Thanks,
Tirthankar



Frank Hofmann wrote:

> On Fri, 13 Jul 2007, Tirthankar wrote:
>
>> Hi Frank,
>>
>> CR 6226326 has been put back to s10u3 also. It doesnt display the 
>> parameters. My understanding is it essentially makes ::findstack work 
>> on an AMD64 core.
>
>
> It was put back into onnv together with the save_args support, for 
> which I cannot find the bugID right now; the latter is what matters, 
> it's _NOT_ backported. Only opensolaris/onnv.
>
Ok I understand. Will try to find the CR

>>
>> The blog is a good pointer to find the parameters, but I would be 
>> more happy if mdb could displaythe parametes like it does for sparc 
>> cores. Makes a debuggers life much easier :)
>
>
> That's why you have the feature in OpenSolaris - to make your life 
> easier ...
>
Unfortunately our products primary platform is S10 sokind of stuck with 
that.

> Btw, it's not _that_ much easier on SPARC. You don't know whether your 
> argument registers have been re-used. On the (good) chance that they 
> have not, you might get away with not having to look at the 
> disassembly. But then, that's not _always_ the case.
>
Ya I agree with you. Justthat I am more familiar with spark debugging :)

> FrankH.
>
>>
>> Thanks,
>> Tirthankar
>>
>>
>>
>> Frank Hofmann wrote:
>>
>>> On Sun, 8 Jul 2007, Tirthankar wrote:
>>>
>>>> Hi,
>>>>
>>>> I am trying to debug a core from a AMD64 machine running S10u3.
>>>>
>>>> MDB is unable to show any parameters in the stack backtrace
>>>
>>>
>>>
>>> Yes, stacktraces with arguments shown were only integrated in 
>>> onnv/OpenSolaris via:
>>>
>>> 6226326 Need to improve stack tracing on x86
>>>
>>> This works via compiler support - onnv/OpenSolaris is compiled in 
>>> such a way that the generated assembly code stores function 
>>> arguments on the stack as well as in the (ABI-mandated) registers. 
>>> This way, mdb can show function arguments in stacktraces.
>>>
>>> Solaris 10 doesn't do that. You'll need to do a manual heuristic. 
>>> ACT is able to perform some of this work but it's not perfect. The 
>>> whole shebang of how argument passing on AMD64 works and which 
>>> heuristics are needed so that arguments can be reconstructed from 
>>> the code flow is explained in:
>>>
>>> http://opensolaris.org/os/community/documentation/doc_index/dev/
>>>
>>> See "Crashdump Analysis". The file is:
>>>
>>> http://opensolaris.org/os/community/documentation/files/book.pdf
>>>
>>> FrankH.
>>>
>>>>
>>>> cfa100 @ /net/coresvr/export/cores1/6570886plipstick1 $ mdb 5
>>>> mdb: warning: dump is from SunOS 5.10 Generic_125101-07; dcmds and
>>>> macros may not match kernel implementation
>>>> Loading modules: [ unix krtld genunix dtrace specfs 
>>>> cpu.AuthenticAMD.15
>>>> uppc pcplusmp ufs ipc ip sctp usba uhci s1394 fcp fctl emlxs qlc 
>>>> nca md
>>>> lofs crypto zfs random cpc fcip logindmux ptm sppp ]
>>>> >
>>>> > ::status
>>>> debugging crash dump vmcore.5 (64-bit) from plipstick1
>>>> operating system: 5.10 Generic_125101-07 (i86pc)
>>>> panic message: BAD TRAP: type=d (#gp General protection)
>>>> rp=fffffe8002012b80 addr=80a8000
>>>> dump content: kernel pages only
>>>> > $c
>>>> __1cG_SListJfind_elem6Mpvppn0AIListElem__3_+0x45()
>>>> __1cSservice_admin_implN_unreferenced6Mpv_v_+0x3c()
>>>> __1cPreplica_handlerNunref_by_ckpt6M_v_+0x172()
>>>> __1cGhxdoorNunref_by_ckpt6M_v_+0x182()
>>>> __1cOhxdoor_managerPrelease_by_ckpt6MrnJhxdoor_id__v_+0x116()
>>>> __1cTckpt_handler_serverHprocess6MrnHservice__v_+0x2cb()
>>>> __1cJckpt_elemHexecute6M_v_+0x4d()
>>>> __1cTthreadpool_worker_tVdeferred_task_handler6M_v_+0x184()
>>>> __1cKthreadpoolOthread_handler6FpnTthreadpool_worker_t__v_+0x25()
>>>> cllwpwrapper+0x106()
>>>> thread_start+8()
>>>> >
>>>>
>>>> This is a serious limitation. I finally used ACT to see the parameters
>>>> but it also was not showing proper parameters all the time.
>>>>
>>>> Is this a known issue ?
>>>> Is there any other way to see the parameters ?
>>>>
>>>> -- 
>>>> Thanks,
>>>> Tirthankar
>>>>
>>>> _______________________________________________
>>>> mdb-discuss mailing list
>>>> mdb-discuss@opensolaris.org
>>>>
>>
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