SIGSEGV while Parse::optimize_inlining an invokedynamic call.

[Christian Thalinger]

[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

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
> _______________________________________________
> mlvm-dev mailing list
> mlvm-dev at openjdk.java.net
> http://mail.openjdk.java.net/mailman/listinfo/mlvm-dev