Re: [PATCH] elf: Do not check for loader mmap on tst-decorate-maps (BZ 31553)

[Adhemerval Zanella Netto <adhemerval.zanella@linaro.org>]

On 22/04/24 07:55, Simon Chopin wrote:
> On mar. 26 mars 2024 10:47:42, Adhemerval Zanella wrote:
>> On some architectures and depending on the page size, the loader can
>> also allocate some memory during dependencies loading and it will be
>> marked as 'loader malloc'.  However, if the system page size is
>> large enough, the initial data page will be enough for all required
>> allocation and there will be no extra loader mmap.  To avoid false
>> negatives, the test does not check for such pages.
>>
>> Checked on powerpc64le-linux-gnu with 64k pagesize.
> 
> Tested in similar conditions.
> Altogether it looks good, I just have one minor whitespace nitpick.
> 
>> ---
>>  elf/tst-decorate-maps.c | 12 ++++++------
>>  1 file changed, 6 insertions(+), 6 deletions(-)
>>
>> diff --git a/elf/tst-decorate-maps.c b/elf/tst-decorate-maps.c
>> index 85ba5ce939..6d04344ba2 100644
>> --- a/elf/tst-decorate-maps.c
>> +++ b/elf/tst-decorate-maps.c
>> @@ -56,7 +56,6 @@ struct proc_maps_t
>>    int n_user_threads;
>>    int n_arenas;
>>    int n_malloc_mmap;
>> -  int n_loader_malloc_mmap;
> 
> OK
> 
>>  };
>>
>>  static struct proc_maps_t
>> @@ -82,8 +81,12 @@ read_proc_maps (void)
>>  	r.n_arenas++;
>>        else if (strstr (line, "[anon: glibc: malloc]") != NULL)
>>  	r.n_malloc_mmap++;
>> -      else if (strstr (line, "[anon: glibc: loader malloc]") != NULL)
>> -	r.n_loader_malloc_mmap++;
>> +      /* On some architectures and depending on the page size, the loader can
>> +	 also allocate some memory during dependencies loading and it will be
>> +	 marked as 'loader malloc'.  However, if the system page size is large
>> +	 enough, the initial data page will be enough for all required
>> +	 allocation and there will be no extra loader mmap.  To avoid false
>> +	 negatives, the test does not check for such pages.  */
> 
> Whitespace mixup here? The first line of the comment block appears to be
> using a different indentation to the rest of the block.

Hum, I used whitespace because it does not really fit for the indentation
of the 'while'.  The rest of patch use tab because it then allows it.

> 
> Good call on leaving an explicit comment!
> 
>>      }
>>    free (line);
>>    xfclose (f);
>> @@ -148,8 +151,6 @@ do_test_threads (bool set_guard)
>>      TEST_COMPARE (r.n_user_threads, num_user_threads);
>>      TEST_COMPARE (r.n_arenas, expected_n_arenas);
>>      TEST_COMPARE (r.n_malloc_mmap, 1);
>> -    /* On some architectures the loader might use more than one page.  */
>> -    TEST_VERIFY (r.n_loader_malloc_mmap >= 1);
> 
> OK
> 
>>    }
>>
>>    /* Let the threads finish.  */
>> @@ -164,7 +165,6 @@ do_test_threads (bool set_guard)
>>      TEST_COMPARE (r.n_user_threads, 0);
>>      TEST_COMPARE (r.n_arenas, expected_n_arenas);
>>      TEST_COMPARE (r.n_malloc_mmap, 1);
>> -    TEST_VERIFY (r.n_loader_malloc_mmap >= 1);
> 
> OK
> 
>>    }
>>
>>    free (p);
>> --
>> 2.34.1
>>