Re: [PATCH] mm/vmalloc: a slight change of compare target in __insert_vmap_area()

[zhong jiang]

On 2017/6/2 9:45, Wei Yang wrote:
> On Fri, May 26, 2017 at 09:55:31AM +0800, zhong jiang wrote:
>> On 2017/5/26 9:36, Wei Yang wrote:
>>> On Thu, May 25, 2017 at 11:04:44AM +0800, zhong jiang wrote:
>>>> I hit the overlap issue, but it  is hard to reproduced. if you think it is safe. and the situation
>>>> is not happen. AFAIC, it is no need to add the code.
>>>>
>>>> if you insist on the point. Maybe VM_WARN_ON is a choice.
>>>>
>>> Do you have some log to show the overlap happens?
>> Hi  wei
>>
>> cat /proc/vmallocinfo
>> 0xf1580000-0xf1600000  524288 raw_dump_mem_write+0x10c/0x188 phys=8b901000 ioremap
>> 0xf1638000-0xf163a000    8192 mcss_pou_queue_init+0xa0/0x13c [mcss] phys=fc614000 ioremap
>> 0xf528e000-0xf5292000   16384 n_tty_open+0x10/0xd0 pages=3 vmalloc
>> 0xf5000000-0xf9001000 67112960 devm_ioremap+0x38/0x70 phys=40000000 ioremap
> These two ranges overlap.
>
> This is hard to say where is the problem. From the code point of view, I don't
> see there is possibility to allocate an overlapped range.
>
> Which version of your kernel?
> Hard to reproduce means just see once? 
  yes, just once.  I have also no see any problem from the code.   The kernel version is linux 4.1.
 but That indeed exist. 

 Thanks
zhongjiang
>> 0xfe001000-0xfe002000    4096 iotable_init+0x0/0xc phys=20001000 ioremap
>> 0xfe200000-0xfe201000    4096 iotable_init+0x0/0xc phys=1a000000 ioremap
>> 0xff100000-0xff101000    4096 iotable_init+0x0/0xc phys=2000a000 ioremap
>>
>> I hit the above issue, but the log no more useful info. it just is found by accident.
>> and it is hard to reprodeced. no more info can be supported for further investigation.
>> therefore, it is no idea for me. 
>>
>> Thanks
>> zhongjinag
>>