SIGSEGV while Parse::optimize_inlining an invokedynamic call.

[Christian Thalinger]

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 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

It's not a duplicate of 7055941.  I filed:

7092712: JSR 292: unloaded invokedynamic call sites can lead to a crash with signature types not on BCP

-- Christian

> 
> 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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