Re: [PATCH] perf kmem: Fix memory leak in compact_gfp_flags()

[Yunfeng Ye]

On 2019/10/16 22:08, Arnaldo Carvalho de Melo wrote:
> Em Wed, Oct 16, 2019 at 09:19:54PM +0800, Yunfeng Ye escreveu:
>>
>>
>> On 2019/10/16 21:09, Arnaldo Carvalho de Melo wrote:
>>> Em Wed, Oct 16, 2019 at 10:04:03AM -0300, Arnaldo Carvalho de Melo escreveu:
>>>> Em Wed, Oct 16, 2019 at 04:38:45PM +0800, Yunfeng Ye escreveu:
>>>>> The memory @orig_flags is allocated by strdup(), it is freed on the
>>>>> normal path, but leak to free on the error path.
>>>>
>>>> Are you using some tool to find out these problems? Or is it just visual
>>>> inspection?
>>>
>> By a static code anaylsis tool which not an open source tool. thanks.
> 
> Ok, so please state that next time, just for the fullest possible
> disclosure and for people to realize to what extent problems in the
> kernel and in tooling hosted in the kernel is being fixed by such tools.
> 
> I.e. you don't need to release the tool, not even give out its name,
> just something like:
> 
> "Found by internal static analysis tool."
> 
ok, thanks.

> Thanks,
> 
> - Arnaldo
>  
>>> Anyway, applied after adding this to the commit log message:
>>>
>>> Fixes: 0e11115644b3 ("perf kmem: Print gfp flags in human readable string")
>>>
>> ok, thanks.
>>
>>> - Arnaldo
>>>  
>>>> - Arnaldo
>>>>  
>>>>> Fix this by adding free(orig_flags) on the error path.
>>>>>
>>>>> Signed-off-by: Yunfeng Ye <yeyunfeng@xxxxxxxxxx>
>>>>> ---
>>>>>  tools/perf/builtin-kmem.c | 1 +
>>>>>  1 file changed, 1 insertion(+)
>>>>>
>>>>> diff --git a/tools/perf/builtin-kmem.c b/tools/perf/builtin-kmem.c
>>>>> index 1e61e353f579..9661671cc26e 100644
>>>>> --- a/tools/perf/builtin-kmem.c
>>>>> +++ b/tools/perf/builtin-kmem.c
>>>>> @@ -691,6 +691,7 @@ static char *compact_gfp_flags(char *gfp_flags)
>>>>>  			new = realloc(new_flags, len + strlen(cpt) + 2);
>>>>>  			if (new == NULL) {
>>>>>  				free(new_flags);
>>>>> +				free(orig_flags);
>>>>>  				return NULL;
>>>>>  			}
>>>>>
>>>>> -- 
>>>>> 2.7.4.3
>>>>
>>>> -- 
>>>>
>>>> - Arnaldo
>>>
>