Re: Is it a lapsus calami in init_io_cache?

Good identification Mr. Left,

Just adding some addtional information

Refernce:
file:= \mysql-5.6.7-rc\mysys\mf_iocache.c Line:= 262

Mutex will be never be cleared as sizeof(info)  will return 4 as info
is pointer to IO_CACHE, so the first four bytes of
info->append_buffer_lock will be set to 0;


Regards,
Shaukat Mahmood Ahmad


On Wed, Oct 31, 2012 at 6:06 PM, Jon Olav Hauglid
<[email protected]> wrote:
> Hello,
>
>
> On 10/27/2012 07:33 AM, Mr. Left wrote:
>>
>> Hi, all
>> I am reading the source code of mysql 5.6.6-m9, and i found the code below
>> in function:init_io_cache
>>
>> /* Clear mutex so that safe_mutex will notice that it's not initialized */
>> memset(&info->append_buffer_lock, 0, sizeof(info));
>>
>> I want to know why use sizeof(info) instead of
>> sizeof(info->append_buffer_lock) ?
>
>
> Good question :-)
> It certainly looks like a bug.
>
> Thanks for making us aware of this issue!
> I've reported it as http://bugs.mysql.com/bug.php?id=67437
>
> --- Jon Olav Hauglid, Principal Software Engineer MySQL, Oracle.
>
>
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