[Crash-utility] Why module's global symbol cannot be displayed in crash?

[Lei Wen]

Dave,

On Tue, Mar 19, 2013 at 10:31 PM, Dave Anderson <anderson at redhat.com> wrote:
>
>
> ----- Original Message -----
>> Hi list,
>>
>> I find in current 6.1.4 crash, when load module with "mod -S",
>> only module's function symbol could be parsed out.
>>
>> But for module's global variant, crash cannot find related symbol...
>> Any idea for this?
>>
>
> Without the debuginfo data from the module.ko.debug file, crash
> gets all of its module symbol data from the kernel.  So it uses
> what's available in the in-kernel /proc/kallsyms list plus the
> information stored in each module's "struct module".  The
> store_module_symbols_v2() function does the work.
>
> If "mod -[sS]" is used, then crash has access to full debuginfo data
> from the module.ko.debug file.  In that case, the store_load_module_symbols()
> function does the work.
>

For current, what I saw is when I have loaded the module, only
the t or T type symbol is installed, while others like d or D type it
would not be loaded at all...

While for one symbol, I already knows its member has a specific
magic number, so that I search the memory, and find its virtual
address becomes to 0xexxxxxxx, not the 0xbfxxxxxx.
So does it mean the debuginfo in that module only has text related,
while data type are all muted, and why?...


Thanks,
Lei