Re: [LTP] MAP_LOCKED issue in mmap with MAP_ANYNOMOUS

[Jan Stancek <jstancek@redhat.com>]

----- Original Message -----
> From: "Satish Gedela" <satish.gedela@lge.com>
> To: ltp-list@lists.sourceforge.net
> Sent: Friday, 20 March, 2015 6:28:34 AM
> Subject: [LTP] MAP_LOCKED issue in mmap with MAP_ANYNOMOUS
> 
> Dear all,
> 
> I am newbie to open source, forgive me with text format
> I am trying to run  LTP with kernel 3.16 on target board having cortex A9
> processor ,
> Facing issue with below test case:
> Test script  name: "memcg_function_test.sh"
> Test case description:  "Test mmap(locked) + alloc_mem > limit_in_bytes"
> 
> Analysis:  memcg_function_test.sh   -----> test_proc_kill
> 						                  ------->memcg_lib.sh
> 									             -------->memcg_process
>     memcg_process
>     ------>ltp/testcases/kernel/controllers/memcg/functional/memcg_process.c
>   
> mmap_lock1 () function is calling in memcg_process.c and
> it calls mmap function with flags MAP_PRIVATE | MAP_ANYNOMOUS | MAP_LOCKED
> {noformat}
> p = mmap(NULL, memsize, PROT_WRITE | PROT_READ,
>       MAP_PRIVATE | MAP_LOCKED, 0, 0);
> {noformat}
> 
> but man page of mmap is mentioned as:
> {noformat}
> MAP_ANONYMOUS
>         The  mapping  is  not  backed  by  any  file; its contents are
>         initialized to zero.  The fd and offset arguments are
>         ignored; however, some implementations require fd to be -1 if
>         MAP_ANONYMOUS (or MAP_ANON) is specified, and portable
>         applications should ensure this.  The use of MAP_ANONYMOUS in
>         conjunction with MAP_SHARED is only supported on Linux
>         since kernel 2.4.
> {noformat}
> 
> In my case, we are trying to lock the pages with flags  MAP_PRIVATE |
> MAP_ANYNOMOUS |  MAP_LOCKED  and  it is failing.

Hi,

failing how? EINVAL or something else?
Do you see mmap14 failing as well? If so, can you run it via strace?

Regards,
Jan

> and with  MAP_SHARED | MAP_ANYNOMOUS |  MAP_LOCKED , it is failing
> but with MAP_PRIVATE | MAP_LOCKED and
> with MAP_SHARED | MAP_LOCKED it is working.
> 
> Is there any changes made to kernel or
> test case has to update with MAP_SHARED instead of MAP_PRIVATE flag.
> 
> Thank you in advance.
> Regards
> Satish.G
> 
>    
> 
> 
> 
> 
> 
>     																															 
> 
> 
> 
>   
> 
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