PING: RFR: 8241439: jdk.NativeLibraryEvent hooks all opened regular files

[Yasumasa Suenaga]

Hi Chihiro,

Thanks for your comment!

On 2020/06/06 22:04, Chihiro Ito wrote:
> Hi Yasumasa,
> 
> In the following code, like the if statement in the base variable, you
> should strictly use 0 and NULL.
> if (top < phdr _ top) {

I think you mean I should add NULL check to conditions for `top`.
I uploaded new webrev. Is it ok?

   http://cr.openjdk.java.net/~ysuenaga/JDK-8241439/webrev.02/


Thanks,

Yasumasa


> Regards,
> Chihiro
> 
> 2020年6月4日(木) 20:26 Yasumasa Suenaga <suenaga at oss.nttdata.com>:
>>
>> Hi all,
>>
>> Could you review this change?
>>
>>>>     JBS: https://bugs.openjdk.java.net/browse/JDK-8241439
>>>>     webrev: http://cr.openjdk.java.net/~ysuenaga/JDK-8241439/webrev.01/
>>
>> I want to merge it to JDK 15.
>> I've got a reviewer, then I need one more reviewer to push.
>>
>>
>> Regards,
>>
>> Yasumasa
>>
>>
>> On 2020/05/26 9:25, Yasumasa Suenaga wrote:
>>> Hi all,
>>>
>>> I've sent review request last month, but nobody has reviewed. Could you review it?
>>>
>>>>     JBS: https://bugs.openjdk.java.net/browse/JDK-8241439
>>>>     webrev: http://cr.openjdk.java.net/~ysuenaga/JDK-8241439/webrev.01/
>>>
>>> os::get_loaded_modules_info() has introduced in JDK-8056242, and it says this function is for dll/so/dylibs.
>>> In fact, os::get_loaded_modules_info() uses EnumProcessModules() in Windows.
>>>
>>> In Linux, get_loaded_modules_info() depends on /proc/<PID>/maps, so it hooks regular files (e.g. JAR, CDS archive), and hooks multiple memory regions by one shared library.
>>> We should merge same library to one event, and should not hook regular files (not shared library).
>>>
>>> All comments are welcome.
>>>
>>>
>>> Thanks,
>>>
>>> Yasumasa
>>>
>>>
>>> On 2020/04/16 9:30, Yasumasa Suenaga wrote:
>>>> PING: Could you review it?
>>>>
>>>>     JBS: https://bugs.openjdk.java.net/browse/JDK-8241439
>>>>     webrev: http://cr.openjdk.java.net/~ysuenaga/JDK-8241439/webrev.01/
>>>>
>>>>
>>>> Yasumasa
>>>>
>>>>
>>>> On 2020/04/09 16:00, Yasumasa Suenaga wrote:
>>>>> Hi all,
>>>>>
>>>>> Please review this change:
>>>>>
>>>>>     JBS: https://bugs.openjdk.java.net/browse/JDK-8241439
>>>>>     webrev: http://cr.openjdk.java.net/~ysuenaga/JDK-8241439/webrev.00/
>>>>>
>>>>> HotSpot has os::get_loaded_modules_info() to get all loaded native libraries, however it would call callback in twice on same library on Linux. Also it would call callback even if the file is not a library.
>>>>>
>>>>> We can see this problem in jdk.NativeLibrary JFR event as below:
>>>>>
>>>>>
>>>>> ```
>>>>> jdk.NativeLibrary {
>>>>>      startTime = 16:59:06.621
>>>>>      name = "/usr/lib64/libc-2.30.so"
>>>>>      baseAddress = 0x7FDB06ACC000
>>>>>      topAddress = 0x7FDB06AF1000
>>>>> }
>>>>>
>>>>> jdk.NativeLibrary {
>>>>>      startTime = 16:59:06.621
>>>>>      name = "/usr/lib64/libc-2.30.so"
>>>>>      baseAddress = 0x7FDB06AF1000
>>>>>      topAddress = 0x7FDB06C40000
>>>>> }
>>>>>
>>>>>       :
>>>>>
>>>>> ```
>>>>>
>>>>> ```
>>>>> jdk.NativeLibrary {
>>>>>      startTime = 16:59:06.621
>>>>>      name = "/home/ysuenaga/OpenJDK/jdk/build/linux-x86_64-server-fastdebug/images/jdk/lib/server/classes.jsa"
>>>>>      baseAddress = 0x800000000
>>>>>      topAddress = 0x800007000
>>>>> }
>>>>> ```
>>>>>
>>>>> This change uses dl_iterate_phdr() to get them, so these problem has gone.
>>>>>
>>>>>
>>>>> Thanks,
>>>>>
>>>>> Yasumasa