RFR(T) : 8195060 : vm/mlvm/anonloader/stress/byteMutation intermittently times out

[Vladimir Kozlov]

So the test filters out invalid class file before executing? Good then.

Thanks,
Vladimir

On 2/13/19 9:35 AM, Igor Ignatyev wrote:
> in its current state, the test changes 4 random bytes to random values, and w/ <clinit> being[1] I don't see it possible to get valid classfile w/ an infinite recursion in <clinit>.
> 
> Thanks,
> -- Igor
> 
> [1]
>>    static {};
>>      descriptor: ()V
>>      flags: (0x0008) ACC_STATIC
>>      Code:
>>        stack=6, locals=0, args_size=0
>>           0: ldc           #8                  // String %65500c%X
>>           2: iconst_2
>>           3: anewarray     #9                  // class java/lang/Object
>>           6: dup
>>           7: iconst_0
>>           8: bipush        99
>>          10: invokestatic  #10                 // Method java/lang/Character.valueOf:(C)Ljava/lang/Character;
>>          13: aastore
>>          14: dup
>>          15: iconst_1
>>          16: invokestatic  #11                 // Method vm/mlvm/share/Env.getRNG:()Ljava/util/Random;
>>          19: invokevirtual #12                 // Method java/util/Random.nextLong:()J
>>          22: invokestatic  #13                 // Method java/lang/Long.valueOf:(J)Ljava/lang/Long;
>>          25: aastore
>>          26: invokestatic  #14                 // Method java/lang/String.format:(Ljava/lang/String;[Ljava/lang/Object;)Ljava/lang/String;
>>          29: putstatic     #2                  // Field theDrumIsTheDrumIsTheDrumIsTheDrumIsTheDrumIsTheDrumIsTheDrumIsTheDrumIsTheDrumIsTheDrumIsTheDrumIsTheDrumIsTheDrumIsTheDrumIsTheDrumIsTheDrumIsTheDrumIsTheDrumIsTheDrumIsTheDrumIsTheDrumIsTheDrumIsTheDrumIsTheDrumIsTheDrum:Ljava/lang/String;
>>          32: return
>>        LineNumberTable:
>>          line 31: 0
>>          line 32: 10
>>          line 31: 32
> 
>> On Feb 13, 2019, at 9:28 AM, Vladimir Kozlov <vladimir.kozlov at oracle.com> wrote:
>>
>> Can it randomly generate infinite recursions in <clinit> method too so your fix would be not enough? Or only <init>?
>>
>> Thanks,
>> Vladimir
>>
>> On 2/12/19 7:20 PM, Igor Ignatyev wrote:
>>> http://cr.openjdk.java.net/~iignatyev/8195060/webrev.00/
>>>> 2 lines changed: 0 ins; 0 del; 2 mod;
>>> Hi all,
>>> could you please review this one-line patch for vmTestbase/vm/mlvm/anonloader/stress/ tests? the goal of these tests is to check that loading of anonymous classes won't lead to a crash and/or a hang, byteMutation test uses a randomly changed class file, which in some cases might lead to infinite recursions in <init> method. as the tests don't need to create an instance of loaded anonymous class to achieve their goal, the patch replaces Class::newInstance call w/ Unsafe::ensureClassInitialized to guarantee that we try to load, link and initialize classes.
>>> webrev: http://cr.openjdk.java.net/~iignatyev/8195060/webrev.00/
>>> JBS: https://bugs.openjdk.java.net/browse/JDK-8195060
>>> testing:
>>> - vmTestbase/vm/mlvm/anonloader/stress/ tests
>>> - manually verified that the tests still can fail by running w/ Xverify:none
>>> Thanks,
>>> -- Igor
>