SIGSEGV while Parse::optimize_inlining an invokedynamic call.
Sebastian Sickelmann
sebastian.sickelmann at gmx.de
Mon Sep 19 07:40:22 PDT 2011
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.
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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