SIGSEGV while Parse::optimize_inlining an invokedynamic call.

Sebastian Sickelmann sebastian.sickelmann at gmx.de
Mon Sep 19 06:04:46 PDT 2011


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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