lkml.org 
[lkml]   [2018]   [Apr]   [17]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH 2/2] mm: vmalloc: Pass proper vm_start into debugobjects
From
Date


On 4/17/2018 8:39 AM, Anshuman Khandual wrote:
> On 04/16/2018 05:39 PM, Chintan Pandya wrote:
>>
>>
>> On 4/13/2018 5:31 PM, Anshuman Khandual wrote:
>>> On 04/13/2018 05:03 PM, Chintan Pandya wrote:
>>>> Client can call vunmap with some intermediate 'addr'
>>>> which may not be the start of the VM area. Entire
>>>> unmap code works with vm->vm_start which is proper
>>>> but debug object API is called with 'addr'. This
>>>> could be a problem within debug objects.
>>>>
>>>> Pass proper start address into debug object API.
>>>>
>>>> Signed-off-by: Chintan Pandya <cpandya@codeaurora.org>
>>>> ---
>>>> mm/vmalloc.c | 4 ++--
>>>> 1 file changed, 2 insertions(+), 2 deletions(-)
>>>>
>>>> diff --git a/mm/vmalloc.c b/mm/vmalloc.c
>>>> index 9ff21a1..28034c55 100644
>>>> --- a/mm/vmalloc.c
>>>> +++ b/mm/vmalloc.c
>>>> @@ -1526,8 +1526,8 @@ static void __vunmap(const void *addr, int
>>>> deallocate_pages)
>>>> return;
>>>> }
>>>> - debug_check_no_locks_freed(addr, get_vm_area_size(area));
>>>> - debug_check_no_obj_freed(addr, get_vm_area_size(area));
>>>> + debug_check_no_locks_freed(area->addr, get_vm_area_size(area));
>>>> + debug_check_no_obj_freed(area->addr, get_vm_area_size(area));
>>>
>>> This kind of makes sense to me but I am not sure. We also have another
>>> instance of this inside the function vm_unmap_ram() where we call for
>> Right, I missed it. I plan to add below stub in v2.
>>
>> --- a/mm/vmalloc.c
>> +++ b/mm/vmalloc.c
>> @@ -1124,15 +1124,15 @@ void vm_unmap_ram(const void *mem, unsigned int
>> count)
>> BUG_ON(addr > VMALLOC_END);
>> BUG_ON(!PAGE_ALIGNED(addr));
>>
>> - debug_check_no_locks_freed(mem, size);
>> -
>> if (likely(count <= VMAP_MAX_ALLOC)) {
>> + debug_check_no_locks_freed(mem, size);
>
> It should have been 'va->va_start' instead of 'mem' in here but as
> said before it looks correct to me but I am not really sure.

vb_free() doesn't honor va->va_start. If mem is not va_start and
deliberate, one will provide proper size. And that should be okay
to do as per the code. So, I don't think this particular debug_check
should have passed va_start in args.

>

Chintan
--
Qualcomm India Private Limited, on behalf of Qualcomm Innovation Center,
Inc. is a member of the Code Aurora Forum, a Linux Foundation
Collaborative Project

\
 
 \ /
  Last update: 2018-04-17 07:11    [W:0.057 / U:0.640 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site