Re: [Xen-devel] Hidden symbol when debugging hypervisor

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 30.04.14 at 12:07, <george.dunlap@xxxxxxxxxxxxx> wrote:
> On 04/30/2014 10:39 AM, Juergen Gross wrote:
>> On 30.04.2014 11:26, George Dunlap wrote:
>>> On 04/30/2014 10:02 AM, Dietmar Hahn wrote:
>>>> Hi,
>>>>
>>>> while debugging a vmcore with the crash tool I stumpled over a 
>>>> little problem.
>>>> I wanted to look at the "struct csched_private" of credit scheduler 
>>>> and got
>>>> the contents of the "struct csched_private" of credit2.
>>>> The debug informations of the hypervisor contain 2 entries
>>>>   <1><b185e>: Abbrev Number: 8 (DW_TAG_structure_type)
>>>>      <b185f>   DW_AT_name        : (indirect string, offset: 0x9d8d):
>>>> csched_private
>>>> and
>>>>   <1><c0677>: Abbrev Number: 25 (DW_TAG_structure_type)
>>>>      <c0678>   DW_AT_name        : (indirect string, offset: 0x9d8d):
>>>> csched_private
>>>>
>>>> The first is credit and the second credit2. It seems in the crash 
>>>> command the
>>>> second entry wins :-(.
>>>>
>>>> Maybe crash has the possibility somewhere to get access to the 
>>>> second structure
>>>> (I couldn't find it) but for simplicity it would be better to have 
>>>> different
>>>> names
>>>> I think.
>>>> Are there any reasons not to rename
>>>> struct csched_private -> struct c2sched_private
>>>> or whatever?
>>>
>>> No reasons at all -- the naming is an artifact of development. Feel 
>>> free to
>>> send a patch renaming it.
>>
>> I tried it once: 
>> http://lists.xen.org/archives/html/xen-devel/2013-02/msg02255.html 
>>
>> Jan didn't like it.
> 
> It looks like he was only thinking about backtraces, not about cscope or 
> about debugging core dumps.  Jan, do you have another solution for 
> those, or shall we go ahead and change the names?

If you're happy with the names getting changed, so be it. I have no
alternative suggestion. I simply would have expected that in year
2014 tools can deal with situations like this (i.e. find the applicable
type rather than the first, last, or a random one). Dwarf debug info
certainly has all the necessary information for that to happen.

Jan


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