SIGSEGV while Parse::optimize_inlining an invokedynamic call.

Christian Thalinger christian.thalinger at oracle.com
Tue Sep 20 01:32:17 PDT 2011 

On Sep 19, 2011, at 4:40 PM, Sebastian Sickelmann wrote:

> Hi,
> 
> i tried to simplify the TestNew2 class. But now it is to simple.
> The crash is gone. I tried to make the process between Main and NEW2 
> more complex, but this doesn't brings the crash back.
> 
> i uploaded the new jar to
> 
> http://oss-patches.24.eu/crashreport/InvokeDynamic/2011-09-17/crash2.jar
> 
> 
> Can you send me your suggested code for TestNew2 class as pseudo-code. I 
> will assemble and test it.

This is what I have now and it still reproduces the crash:

// class version 51.0 (51)
// access flags 0x1
public class TestNew2 {

  // compiled from: TestNew2.txt
  // debug info: 

  // access flags 0x9
  public static testIt()V
   L0
    LINENUMBER 3 L0
    NEW NEW2
    DUP
    INVOKESPECIAL NEW2.<init> ()V
    DUP
    INVOKEDYNAMIC cause (LNEW2;)Ljava/lang/Throwable; [Bootstrapper.getFunction(Ljava/lang/invoke/MethodHandles$Lookup;Ljava/lang/String;Ljava/lang/invoke/MethodType;)Ljava/lang/invoke/CallSite; (6)]
    POP
    DUP
    NEW java/lang/RuntimeException
    DUP
    LDC "NEW"
    INVOKESPECIAL java/lang/RuntimeException.<init> (Ljava/lang/String;)V
    INVOKEDYNAMIC cause (LNEW2;Ljava/lang/Throwable;)V [Bootstrapper.setFunction(Ljava/lang/invoke/MethodHandles$Lookup;Ljava/lang/String;Ljava/lang/invoke/MethodType;)Ljava/lang/invoke/CallSite; (6)]
    INVOKEDYNAMIC cause (LNEW2;)Ljava/lang/Throwable; [Bootstrapper.getFunction(Ljava/lang/invoke/MethodHandles$Lookup;Ljava/lang/String;Ljava/lang/invoke/MethodType;)Ljava/lang/invoke/CallSite; (6)]
    POP
    RETURN
    MAXSTACK = 5
    MAXLOCALS = 0
}

-- Christian

> 
> The new actual disassembly looks like:
> 
> // class version 51.0 (51)
> // access flags 0x1
> public class TestNew2 {
> 
>   // compiled from: TestNew2.txt
>   // debug info:
> 
>   // access flags 0x9
>   public static testIt()V
>    L0
>     LINENUMBER 2 L0
>     NEW NEW2
>     DUP
>     INVOKESPECIAL NEW2.<init> ()V
>     NEW java/lang/RuntimeException
>     DUP
>     LDC "NEW"
>     INVOKESPECIAL java/lang/RuntimeException.<init> (Ljava/lang/String;)V
>     INVOKEDYNAMIC cause (LNEW2;Ljava/lang/Throwable;)V 
> [Bootstrapper.setFunction(Ljava/lang/invoke/MethodHandles$Lookup;Ljava/lang/String;Ljava/lang/invoke/MethodType;)Ljava/lang/invoke/CallSite; 
> (6)]
>     RETURN
>     MAXSTACK = 4
>     MAXLOCALS = 0
> }
> 
> 
> -- Sebastian
> 
> Am 19.09.2011 15:04, schrieb Sebastian Sickelmann:
>> I can do this for you  in a few  hours.if it cannot wait you can clone my demo project mentioned in [0] and change the GEN class before starting the build.xml. The TestNew2.class and the Dissabled TestNew2.txt should be in the temp dir after running build.xml.
>> 
>> Sorry for the previous mail. F*** german autocompletion of my smartphone.
>> 
>> 
>> Sebastian Sickelmann<sebastian.sickelmann at gmx.de>  schrieb:
>> 
>>> I can so this for Sound in a gewesen hours. Info it cannot wait you can clone my demo project mentioned in [0] and change the GEN class before starting the build.xml. The TestNew2.class and the Dissabled TestNew2.txt should bei in the temp dir after running build.xml.
>>> (
>>> 
>>> Christian Thalinger<christian.thalinger at oracle.com>  schrieb:
>>> 
>>>> On Sep 19, 2011, at 11:09 AM, Christian Thalinger wrote:
>>>> 
>>>>> [Moving hotspot-runtime-dev to Bcc]
>>>>> 
>>>>> On Sep 17, 2011, at 9:05 PM, Sebastian Sickelmann wrote:
>>>>> 
>>>>>> Hi,
>>>>>> while doing further investigations on my idea [0] i observed a
>>>>>> reproducable crash of the vm.
>>>>>> It seems to me that it happens while the hotspot tries to inline (i
>>>>>> think) a invokedynamic call.
>>>>>> It happens only in my second Testcases (a case where an exception is
>>>>>> thrown) so i tried
>>>>>> to reduce it to a smaller amount of classes.
>>>>>> 
>>>>>> I reduces the example of my idea to some core classes which i packed to [1].
>>>>>> You can run the example starting the Main class. If you start it with
>>>>>> -Xint no crash happens.
>>>>>> I have packed it with the java-source or with disassembled classfile for
>>>>>> the invokedynamic call.
>>>> What format is the disassembled class file?  How can I assemble it to a class file?  I'd like to remove the println stuff.
>>>> 
>>>> -- Christian
>>>> 
>>>>>> What is the Programm doing?
>>>>>> 
>>>>>> Main starts TestNew2.testIt() 20000 times and prints out the thrown
>>>>>> exception every time.
>>>>>> TestNew2 is a generated class which does something like(just with out
>>>>>> the local variable):
>>>>>>    NEW2 o = new NEW2();
>>>>>>    Throwable cause = INVOKEDYNAMIC cause (LNEW2;)Ljava/lang/Throwable;
>>>>>> [Bootstrapper.getFunction(Ljava/lang/invoke/MethodHandles$Lookup;Ljava/lang/String;Ljava/lang/invoke/MethodType;)Ljava/lang/invoke/CallSite;
>>>>>> (6)]
>>>>>>    // Which is effective cause = o.getCause();
>>>>>>    System.out.println(cause);
>>>>>>    Throwable newCause = new RuntimeException("NEW");
>>>>>>    INVOKEDYNAMIC cause (LNEW2;Ljava/lang/Throwable;)V
>>>>>> [Bootstrapper.setFunction(Ljava/lang/invoke/MethodHandles$Lookup;Ljava/lang/String;Ljava/lang/invoke/MethodType;)Ljava/lang/invoke/CallSite;
>>>>>> (6)]
>>>>>>    // Which is effective o.initCause(newCause) which throws the
>>>>>> exception that is catched by Main.
>>>>>>    The Binding is done via the Bootstrapper class.
>>>>>>        It looks up if the field "NEW2.cause" can be accessed by
>>>>>> TestNew2 which isn't the case and binds the two calls to the methods
>>>>>> NEW2.getCause and NEW2.initCause.
>>>>>> 
>>>>>> 
>>>>>> I have checked it with
>>>>>>    java version "1.7.0"
>>>>>>    Java(TM) SE Runtime Environment (build 1.7.0-b147)
>>>>>>    Java HotSpot(TM) Server VM (build 21.0-b17, mixed mode)
>>>>>> 
>>>>>> i have put my hs_err_pid.log here [2].
>>>>>> 
>>>>>> maybe b127 this is not the newest, but i didn't found a newer one. Maybe
>>>>>> its the same problem as the porter-stemmer (don't interested me much
>>>>>> till now) but -XX:-UseLoopPredicate (which i think should fix it) doen't
>>>>>> solve it.
>>>>>> 
>>>>>> I have cross-checked it also with my local openjdk8 builds.
>>>>>> 
>>>>>> The builds are
>>>>>>    complete build of http://hg.openjdk.java.net/jdk8/jdk8 rev
>>>>>> 28cf2aec4dd7
>>>>>>    and even if i don't think it's a hotspot problem i checked it also
>>>>>>    against my openjdk8 with http://hg.openjdk.java.net/jdk8/tl/jdk/
>>>>>> rev 75d763111eec
>>>>>> 
>>>>>> I am not 100% sure if the error is on my side or if it is on the vm,
>>>>>> maybe i have done something wrong with the invokedynamic. But i think it
>>>>>> is inside hotspot because hotspot / interpreted-mode should work the
>>>>>> same way, isn't it?
>>>>> I can reproduce the bug and it is a VM issue (more precisely a C2 issue).  Although the synopsis mentions deoptimization this is very likely a duplicate of:
>>>>> 
>>>>> 7055941: JSR 292 method handle invocation causes excessive deoptimization for types not on boot class path
>>>>> 
>>>>> The the two classes involved in the is_subtype_of check are in different class loaders:
>>>>> 
>>>>> (dbx) fr 8
>>>>> Current function is ciKlass::is_subtype_of
>>>>>   69     assert(is_loaded()&&  that->is_loaded(), "must be loaded");
>>>>> (dbx) p this->print()
>>>>> <ciInstanceKlass name=NEW2 loader=0xe614c000 loaded=true initialized=true finalized=false subklass=false size=16 flags=public,super super=java/lang/Object ident=715 PERM address=0x858e298>this->print() = (void)
>>>>> (dbx) p that->print()
>>>>> <ciInstanceKlass name=NEW2 loader=0x0 loaded=false ident=722  address=0x858e8b0>that->print() = (void)
>>>>> 
>>>>> Putting your test case on the boot class path makes it work:
>>>>> 
>>>>> $ java Main>  /dev/null
>>>>> Abort
>>>>> $ java -Xbootclasspath/a:. Main>  /dev/null
>>>>> $
>>>>> 
>>>>> I'm looking into it.
>>>>> 
>>>>> -- Christian
>>>>> 
>>>>>> Please let me know if i can make further experiments that helps to
>>>>>> isolate/solve this problem.
>>>>>> 
>>>>>> -- Sebastian
>>>>>> 
>>>>>> Sorry if the oss-patches.24.eu isn't as stable as it should be but this
>>>>>> my only free webspace i have for this actually.
>>>>>> 
>>>>>> [0] http://codingwizard.wordpress.com/2011/09/13/remove-flaws-in-java-apis/
>>>>>> [1] http://oss-patches.24.eu/crashreport/InvokeDynamic/2011-09-17/crash.jar
>>>>>> [2]
>>>>>> http://oss-patches.24.eu/crashreport/InvokeDynamic/2011-09-17/hs_err_pid7339.log
>>>>>> _______________________________________________
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