Possibly something weird about talloc?

[Richard Sharpe]

On Sun, Feb 7, 2016 at 9:33 AM, Ralph Boehme <rb at sernet.de> wrote:
> On Sun, Feb 07, 2016 at 02:13:38PM -0800, Richard Sharpe wrote:
>> Hi folks,
>>
>> I have modified gdb-heap (ssh://git.fedorahosted.org/git/gdb-heap.git) to
>> show useful info about talloc chunks in the heap as well.
>>
>> In looking at the results, I see many cases like this:
>>
>> -----------------------------------------
>>    178: 0x00007f98cdc927f0 -> 0x00007f98cdc9288f      160 bytes
>> talloc:talloc chunk:48 bytes:"struct parmlist_entry" |a0 b4 cb cd 98 7f 00
>> 00 40 be cd cd 98 7f 00 00 00 00 00 00 00 00 00 00 c0 bd cd cd 98 7f 00 00
>> 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 35 07 7f c8 98 7f 00 00 30
>> 00 00 00 00 00 00 00 70 0c 15 e8 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>> 00 00 00 00 00 00 80 00 00 00 00 00 00 00 a0 be cd cd 98 7f 00 00 a0 9f c9
>> cd 98 7f 00 00 90 04 c9 cd 98 7f 00 00 20 be cd cd 98 7f 00 00
>> |.....^?.. at ....^?...............^?..................5.^?..^?..0.......p....................................^?.......^?.......^?..
>> ....^?..|
>> ------------------------------------------
>>
>> It contains a pointer in the chunk header pointing to the structure type.
>>
>> However, I also see entries like this:
>>
>> -------------------------------------------------
>>    177: 0x00007f98cdc92760 -> 0x00007f98cdc927ef      144 bytes
>> talloc:talloc chunk:25 bytes:"/home/samba/etc/smb.conf" |30 b5 cb cd 98 7f
>> 00 00 00 00 00 00 00 00 00 00 a0 b4 cb cd 98 7f 00 00 00 00 00 00 00 00 00
>> 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 c0 27 c9 cd 98 7f 00 00
>> 19 00 00 00 00 00 00 00 70 0c 15 e8 00 00 00 00 00 00 00 00 00 00 00 00 00
>> 00 00 00 00 00 00 00 40 ec c8 cd 98 7f 00 00 2f 68 6f 6d 65 2f 73 61 6d 62
>> 61 2f 65 74 63 2f 73 6d 62 2e 63 6f 6e 66 00 8f c9 cd 98 7f 00 00
>> |0....^?...............^?...........................'...^?..........p.......................@
>> ....^?../home/samba/etc/smb.conf.....^?..|
>> --------------------------------------------------
>>
>> The pointer in the header that should point to the allocation location or
>> type points to the data.
>>
>> When does this happen?
>
> sorry, can't help. But fwiw, maybe this one can:
> <https://github.com/nccgroup/libtalloc>
>
> -Ralph

Yeah, tried it earlier, but it simply did not work.

-- 
Regards,
Richard Sharpe
(何以解憂？唯有杜康。--曹操)