RFR: 8132725: Memory leak in Arguments::add_property function
Daniel D. Daugherty
daniel.daugherty at oracle.com
Thu Aug 27 13:01:01 UTC 2015
On 8/27/15 12:51 AM, David Holmes wrote:
> On 27/08/2015 3:27 PM, Ioi Lam wrote:
>> On the topic of goto, some people like to do this:
>>
>> do {
>> if (...) {
>> break;
>> }
>> ...
>> if (...) {
>> break;
>> }
>> } while (0);
>> // "break" will "goto" here
>>
>> Will this be less of an eyesore than "goto"?
>
> No! A goto by any other name ... :) Might as well just use a goto if
> you are going to resort to such an ugly structure just to avoid using
> goto.
Slightly less ugly than goto in my opinion.
Dan
>
> David
>
>> - Ioi
>>
>>
>> On 8/26/15 2:57 PM, Coleen Phillimore wrote:
>>>
>>> + char* tmp_key = AllocateHeap(key_len + 1, mtInternal);
>>> +
>>> + if (tmp_key == NULL) {
>>> + return false;
>>> }
>>>
>>> AllocateHeap will call vm_exit_out_of_memory if it fails, and not
>>> return NULL. You have to add AllocFailStrategy::RETURN_NULL
>>>
>>> Otherwise, this seems good.
>>>
>>> Thanks for not adding a goto.
>>>
>>> Coleen
>>>
>>>
>>> On 8/26/15 2:05 PM, Dmitry Dmitriev wrote:
>>>> Hello,
>>>>
>>>> Still need a Reviewer. Can someone review this patch? Thank you!
>>>>
>>>> Dmitry
>>>>
>>>> On 25.08.2015 15:27, Dmitry Dmitriev wrote:
>>>>> Hi Ioi,
>>>>>
>>>>> Thank you for review and sponsorship! Still need a Reviewer please.
>>>>>
>>>>> I added assert. Also I fix indention on line 1023 and change "char
>>>>> *var_name" to "char* var_name" to match style which used in this
>>>>> function.
>>>>>
>>>>> webrev 02: http://cr.openjdk.java.net/~ddmitriev/8132725/webrev.02/
>>>>> <http://cr.openjdk.java.net/%7Eddmitriev/8132725/webrev.02/>
>>>>> webrev 02 vs 01:
>>>>> http://cr.openjdk.java.net/~ddmitriev/8132725/webrev.02.vs.01/
>>>>> <http://cr.openjdk.java.net/%7Eddmitriev/8132725/webrev.02.vs.01/>
>>>>>
>>>>> Thanks,
>>>>> Dmitry
>>>>>
>>>>> On 24.08.2015 20:42, Ioi Lam wrote:
>>>>>> Hi Dmitry,
>>>>>>
>>>>>> The new changes look good.
>>>>>>
>>>>>> For defensive programming, I would suggest adding an assert here:
>>>>>>
>>>>>> 1035 if (_java_vendor_url_bug != DEFAULT_VENDOR_URL_BUG) {
>>>>>> assert(_java_vendor_url_bug != NULL, "......");
>>>>>> 1036 os::free((void *)_java_vendor_url_bug);
>>>>>>
>>>>>> I can sponsor the change, but we still need a Reviewer for this
>>>>>> change.
>>>>>>
>>>>>> Thanks
>>>>>> - Ioi
>>>>>>
>>>>>> On 8/24/15 6:21 AM, Dmitry Dmitriev wrote:
>>>>>>> Hi Ioi,
>>>>>>>
>>>>>>> Thank you for comments! Please, see my answers inline.
>>>>>>>
>>>>>>> On 24.08.2015 2:13, Ioi Lam wrote:
>>>>>>>> Hi Dmitry,
>>>>>>>>
>>>>>>>> Is this change part of 8132725?
>>>>>>>>
>>>>>>>> 3904 jint code = set_aggressive_opts_flags();
>>>>>>>> 3905 if (code != JNI_OK) {
>>>>>>>> 3906 return code;
>>>>>>>> 3907 }
>>>>>>> Yes, set_aggressive_opts_flags not check return value of
>>>>>>> add_property function, so I add check to the
>>>>>>> set_aggressive_opts_flags()(lines 1911-1913 in new arguments.cpp)
>>>>>>> and thus now it returns jint.
>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> 1041 if (_java_vendor_url_bug != DEFAULT_VENDOR_URL_BUG) {
>>>>>>>>
>>>>>>>> >> also check (_java_vendor_url_bug != NULL) for sanity?
>>>>>>> I think that this is unnecessary in this case, because
>>>>>>> _java_vendor_url_bug can not be NULL. _java_vendor_url_bug
>>>>>>> initialized to DEFAULT_VENDOR_URL_BUG and changed only in
>>>>>>> add_property function. Before new value is assigned to
>>>>>>> _java_vendor_url_bug it's check for not NULL. Thus, I think that
>>>>>>> check (_java_vendor_url_bug != NULL) is unnecessary in this case.
>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> Also, there's a lot of duplicated "if (eq != NULL) {
>>>>>>>> FreeHeap((void *)key);}". Maybe these can be consolidated with a
>>>>>>>> "goto"? I know lots of people haye goto but it will make the
>>>>>>>> clean up less error prone:
>>>>>>> Thank you for this proposal. Since "goto" is not widely used in
>>>>>>> Hotspot code I decided to refactor current implementation to avoid
>>>>>>> duplication of "if (eq != NULL) { FreeHeap((void *)key);}".
>>>
>>>>>>>
>>>>>>>>
>>>>>>>> bool Arguments::add_property(const char* prop) {
>>>>>>>> ....
>>>>>>>> bool status = false;
>>>>>>>> ....
>>>>>>>> char *_java_command_new = os::strdup(value, mtInternal);
>>>>>>>> if (_java_command_new == NULL) {
>>>>>>>> goto done;
>>>>>>>> }else {
>>>>>>>> if (_java_command != NULL) {
>>>>>>>> os::free(_java_command);
>>>>>>>> }
>>>>>>>> _java_command = _java_command_new;
>>>>>>>> }
>>>>>>>> ....
>>>>>>>> }
>>>>>>>> // Create new property and add at the end of the list
>>>>>>>> PropertyList_unique_add(&_system_properties, key, value);
>>>>>>>> }
>>>>>>>> status = true;
>>>>>>>>
>>>>>>>> done:
>>>>>>>> if (key != prop) {
>>>>>>>> // SystemProperty copy passed value, thus free previously
>>>>>>>> allocated
>>>>>>>> // memory
>>>>>>>> FreeHeap((void *)key);
>>>>>>>> }
>>>>>>>> return status;
>>>>>>>> }
>>>>>>>>
>>>>>>>> Also, using (key != prop) would make the code clearer than (eq !=
>>>>>>>> NULL).
>>>>>>> Fixed!
>>>>>>>
>>>>>>> webrev 01:
>>>>>>> http://cr.openjdk.java.net/~ddmitriev/8132725/webrev.01/
>>>>>>> <http://cr.openjdk.java.net/%7Eddmitriev/8132725/webrev.01/>
>>>>>>> webrev 01 vs 00:
>>>>>>> http://cr.openjdk.java.net/~ddmitriev/8132725/webrev.01.vs.00/
>>>>>>> <http://cr.openjdk.java.net/%7Eddmitriev/8132725/webrev.01.vs.00/>
>>>>>>>
>>>>>>> Thank you,
>>>>>>> Dmitry
>>>>>>>>
>>>>>>>> Thanks
>>>>>>>> - Ioi
>>>>>>>>
>>>>>>>> On 8/13/15 12:55 AM, Dmitry Dmitriev wrote:
>>>>>>>>> Hello,
>>>>>>>>>
>>>>>>>>> Please review this fix which remove memory leak in
>>>>>>>>> Arguments::add_property function. Also, I need a sponsor for
>>>>>>>>> this fix, who can push it.
>>>>>>>>>
>>>>>>>>> Arguments::add_property function allocate memory for key and
>>>>>>>>> value. Then key and values are passed to the
>>>>>>>>> PropertyList_unique_add function which use SystemProperty class
>>>>>>>>> to add or update property value. SystemProperty class maintains
>>>>>>>>> it's own copy of key and value and thus copy passed key and
>>>>>>>>> value. Therefore key and value must be freed in add_property
>>>>>>>>> function(with exception for value in case of
>>>>>>>>> "java.vendor.url.bug" and "sun.java.command" properties).
>>>>>>>>>
>>>>>>>>> In this fix I allocate memory only for key when passed property
>>>>>>>>> contains value. If passed property not contains value, then I
>>>>>>>>> not allocate memory for key and use passed property string.
>>>>>>>>> Value also extracted from passed property string instead of
>>>>>>>>> allocating. To accomplish that I changed declaration of "value"
>>>>>>>>> in several functions from "char *" to "const char *" since
>>>>>>>>> value is not modified in these functions(PropertyList_*
>>>>>>>>> functions, SystemProperty class methods).
>>>>>>>>>
>>>>>>>>> Processing of "java.vendor.url.bug" and "sun.java.command"
>>>>>>>>> properties also corrected. Now when these properties redefined,
>>>>>>>>> then code checks if memory was allocated for special variables
>>>>>>>>> of these properties(checking that not contains default value)
>>>>>>>>> and free it.
>>>>>>>>>
>>>>>>>>> Webrev: http://cr.openjdk.java.net/~ddmitriev/8132725/webrev.00/
>>>>>>>>> <http://cr.openjdk.java.net/%7Eddmitriev/8132725/webrev.00/>
>>>>>>>>> JBS: https://bugs.openjdk.java.net/browse/JDK-8132725
>>>>>>>>> Tested: JPRT(hotspot test set), hotspot all, vm.quick
>>>>>>>>>
>>>>>>>>> Thanks,
>>>>>>>>> Dmitry
>>>>>>>>
>>>>>>>
>>>>>>
>>>>>
>>>>
>>>
>>
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