premain: Crash in Infinispan server code caused by NPE under MethodHandleNative::linkDynamicConstant
ioi.lam at oracle.com
ioi.lam at oracle.com
Thu Sep 19 19:51:28 UTC 2024
On 9/19/24 7:44 AM, Ashutosh Mehra wrote:
>
> As I am cleaning up the code for upstreaming to mainline, I am
> going add an equivalent check in the C code to filter out these
> indy call sites, so they won't be resolved at all during the
> assembly phase. Otherwise, I will run into problems described in
> https://bugs.openjdk.org/browse/JDK-8290417
>
>
> Thanks for the link to the bug. The scenario described in that bug is
> exactly the same as the Infinispan case.
> So if we filter out such cases during indy resolution then it should
> resolve the Infinispan issue as well.
>
> A basic question: why can't CDS handle the lambda proxy class
> generated in useImplMethodHandle mode?
>
If I remember correctly, it has to do with the shape of dynamically
generated bytecode:
public void accept(java.lang.Object);
Code:
0: ldc #28 // Dynamic #0:_:Ljava/lang/invoke/MethodHandle;
2: aload_0
3: getfield #15 // Field arg$1:LTester;
6: aload_1
7: checkcast #30 // class java/lang/String
10: invokevirtual #36 // Method
java/lang/invoke/MethodHandle.invokeExact:(LTester;Ljava/lang/String;)V
13: return
The result of the "ldc" was not symbolically encoded in the generated
class (as the generated class has no permission to access that method).
So the MethodHandle is stored as a binary object in the mirror of this
generated class (with the java.lang.Class::classData field).
Plain CDS doesn't archive class mirrors, so the classData will be lost.
With JEP 483, we should be able to preserve the classData, so I am not
sure why the useImplMethodHandle case is still failing. My plan is to
filter these out for now, but I will get back to it later when I have
more time.
Thanks
- Ioi
> Thanks,
> - Ashutosh Mehra
>
>
> On Thu, Sep 19, 2024 at 1:45 AM <ioi.lam at oracle.com> wrote:
>
> Hi Ashutosh,
>
> I have some update:
>
> The original crash was caused by the "useImplMethodHandle" code in
> InnerClassLambdaMetafactory.java:
>
> // If the target class invokes a protected method
> inherited from a
> // superclass in a different package, or does
> 'invokespecial', the
> // lambda class has no access to the resolved method, or does
> // 'invokestatic' on a hidden class which cannot be
> resolved by name.
> // Instead, we need to pass the live implementation method
> handle to
> // the proxy class to invoke directly. (javac prefers to
> avoid this
> // situation by generating bridges in the target class)
> useImplMethodHandle =
> (Modifier.isProtected(implInfo.getModifiers()) &&
> !VerifyAccess.isSamePackage(targetClass,
> implInfo.getDeclaringClass())) ||
> implKind ==
> MethodHandleInfo.REF_invokeSpecial ||
> implKind ==
> MethodHandleInfo.REF_invokeStatic && implClass.isHidden();
>
> As I am cleaning up the code for upstreaming to mainline, I am
> going add an equivalent check in the C code to filter out these
> indy call sites, so they won't be resolved at all during the
> assembly phase. Otherwise, I will run into problems described in
> https://bugs.openjdk.org/browse/JDK-8290417
>
> Once I get the filtering code working, I will integrate it back to
> premain.
>
> >I am wondering if we can workaround class circularity issues by
> recording class initialization order
> >during training run and use that to guide the initialization
> during assembly phase.
>
> In the production run we take different paths than the training run
>
> (1) some classes are aot-initialized (especially the enums)
> (2) some classes make special CDS calls
>
> so I am not sure if it's possible to get the same initialization
> order as in the training run (or assembly phase).
>
> (more below)
>
> On 9/18/24 9:10 AM, Ashutosh Mehra wrote:
>> Hi Ioi,
>>
>> I was having a similar circularity issue (but in production
>> time) and I just added enough classes to make the NPE go away.
>>
>> I am wondering if you have a test case that reproduces the NPE
>> which prompted you to add these classes:
>>
>> https://github.com/openjdk/leyden/blob/7781109154bf2af89854c7e13aa3e160bb82608e/src/hotspot/share/cds/aotClassInitializer.cpp#L65-L78
>> <https://urldefense.com/v3/__https://github.com/openjdk/leyden/blob/7781109154bf2af89854c7e13aa3e160bb82608e/src/hotspot/share/cds/aotClassInitializer.cpp*L65-L78__;Iw!!ACWV5N9M2RV99hQ!NYvqLbb_Ib2kSdm2fcYVLGby-AiB2TG7KtC1HQHVKLiM-_kRb5mOt8krV5IZfReaYZ0MPadDfa08hQ$>
>>
>> I commented this code and ran the tests under premain but didn't
>> hit the NPE.
>>
> I forgot what the problem was, but it happened for very simple cases.
>
> Thanks
>
> - Ioi
>
>
>> Thanks,
>> - Ashutosh Mehra
>>
>>
>> On Tue, Sep 17, 2024 at 1:11 AM <ioi.lam at oracle.com> wrote:
>>
>> Hi Ashutosh,
>>
>> So this looks like a potential bug (or feature) in the core
>> lib code. When CDS forcefully initializes a class in an
>> unexpected (or untested) order, the "initialization soup" fails.
>>
>> Perhaps a work-around would be to make some harmless calls at
>> the place where CDS was calling into
>> MethodType.createArchivedObjects(). E.g., do something like this:
>>
>> + if (CDSConfig::is_dumping_invokedynamic()) {
>> + // call into Java:
>> jdk.internal.misc::warmupInvokeDynamic();
>> + }
>> // Rewrite and link classes
>> log_info(cds)("Rewriting and linking classes ...");
>>
>> Maybe you can add a new Lambda expressions, MethodHandle
>> invocations, etc, that would hopefully cause
>> PrimitiveClassDescImpl and friends to be initialized in their
>> natural order.
>>
>> Or call class.forName("java.lang.constant.ConstantDescs") ??
>>
>> BTW, you can see my comments in
>> AOTClassInitializer::is_forced_preinit_class():
>>
>> // TODO:
>> // This is needed since JDK-8338532. Without this, when
>> // archived heap objects are used, the class init order
>> is not
>> // expected by the jdk/internal/constant bootstrap code
>> and we
>> // will get a null pointer exception.
>> //
>> // When bootstraping has intricated/fragile order, it's
>> probably
>> // better to archive all related classes in an
>> initialized state
>> // (i.e., take a snapshot). The existing approach in
>> // heapShared::resolve_or_init_classes_for_subgraph_of()
>> won't work.
>> "jdk/internal/constant/PrimitiveClassDescImpl",
>> "jdk/internal/constant/ReferenceClassDescImpl",
>> "java/lang/constant/ConstantDescs",
>> "sun/invoke/util/Wrapper",
>>
>> I was having a similar circularity issue (but in production
>> time) and I just added enough classes to make the NPE go
>> away. For your test case, if you manage to fix in in the
>> assembly run but run into NPE in production run, you might
>> need to add more classes to this list. Yes, it's a hack :-(
>>
>>
>> Thanks
>>
>> - Ioi
>>
>> On 9/13/24 7:05 PM, Ashutosh Mehra wrote:
>>> This is turning out to be a real example of class
>>> initialization soup!
>>> As mentioned during the meeting, I am getting NPE in the
>>> assembly phase when testing the patch [0] that I proposed in
>>> my earlier mail
>>> using a test case inspired by the Infinispan code.
>>> NPE occurs when running the class initializer for
>>> PrimitiveClassDescImpl
>>> Interestingly, PrimitiveClassDescImpl is "forcefully"
>>> initialized by MetaspaceShared::link_shared_classes().
>>>
>>> I couldn't get a stack trace so I relied on exception logs
>>> (using -Xlog:exceptions=trace) to find the cause which
>>> indicate following frames on the stack:
>>>
>>> [0]
>>> jdk/internal/constant/MethodTypeDescImpl::validateArgument(Ljava/lang/constant/ClassDesc;)Ljava/lang/constant/ClassDesc; @
>>> bci 1
>>> [1]
>>> jdk/internal/constant/MethodTypeDescImpl::ofTrusted(Ljava/lang/constant/ClassDesc;[Ljava/lang/constant/ClassDesc;)Ljdk/internal/constant/MethodTypeDescImpl; @
>>> bci 27
>>> [2]
>>> java/lang/constant/ConstantDescs::ofConstantBootstrap(Ljava/lang/constant/ClassDesc;Ljava/lang/String;Ljava/lang/constant/ClassDesc;[Ljava/lang/constant/ClassDesc;)Ljava/lang/constant/DirectMethodHandleDesc; @
>>> bci 47
>>> [3] java/lang/constant/ConstantDescs::<clinit> @ bci 664
>>> [4]
>>> jdk/internal/constant/PrimitiveClassDescImpl::<init>(Ljava/lang/String;)V @
>>> bci 1
>>> [5]
>>> jdk/internal/constant/PrimitiveClassDescImpl::<clinit>(Ljava/lang/String;)V @
>>> bci 6
>>>
>>> Notice that invocation of PrimitiveClassDescImpl::<clinit>
>>> results in initialization of ConstantDescs class (see frame 3).
>>> ConstantDescs::<clinit> @ 664 corresponds to following java
>>> code:
>>>
>>> public static final DirectMethodHandleDesc BSM_CLASS_DATA_AT
>>> = ofConstantBootstrap(CD_MethodHandles, "classDataAt",
>>> CD_Object, CD_int);
>>>
>>> The last parameter CD_int is initialized as:
>>>
>>> public static final ClassDesc CD_int =
>>> PrimitiveClassDescImpl.CD_int;
>>>
>>> So, its value is obtained from
>>> PrimitiveClassDescImpl.CD_int which hasn't been initialized
>>> properly yet. As a result ConstantDescs::CD_int is
>>> assigned null which results in
>>> MethodTypeDescImpl::validateArgument throwing NPE later.
>>> There is a clear class initialization circularity involving
>>> PrimitiveClassDescImpl and ConstantDescs, and the result
>>> depends on which class gets initialized first.
>>>
>>> Without my patch this issue is not seen because
>>> PrimitiveClassDescImpl has already been initialized by the
>>> time MetaspaceShared::link_shared_classes() is called.
>>> Its initialization is triggered by the call to
>>> MethodType::createArchivedObjects().
>>> It also explains why my patch introduced this issue because
>>> it effectively moved the call to
>>> MethodType::createArchivedObjects() after
>>> MetaspaceShared::link_shared_classes().
>>>
>>> [0]
>>> https://github.com/ashu-mehra/leyden/commit/d8f99cce67df1c7b0f7ef8562676df438633a66e
>>> <https://urldefense.com/v3/__https://github.com/ashu-mehra/leyden/commit/d8f99cce67df1c7b0f7ef8562676df438633a66e__;!!ACWV5N9M2RV99hQ!MnS3LSY2PXCCXbHvdyMfR6Nj57XH7Ey7aZuOLmQ__hhE_RhUrKnkzZ0uP8AwLZYcl8lAhhZK3GwoiA$>
>>>
>>> Thanks,
>>> - Ashutosh Mehra
>>>
>>>
>>> On Wed, Sep 11, 2024 at 3:12 PM Ashutosh Mehra
>>> <asmehra at redhat.com> wrote:
>>>
>>> Regarding the WrongMethodTypeException that I mentioned
>>> in my previous email (see pt 3),
>>> this exception happens when lambda proxy class attempts
>>> to invoke the MethodHandle it obtained from the classData:
>>>
>>> public void accept(java.lang.Object);
>>> descriptor: (Ljava/lang/Object;)V
>>> flags: (0x0001) ACC_PUBLIC
>>> Code:
>>> stack=3, locals=2, args_size=2
>>> 0: ldc #26 // Dynamic
>>> #0:_:Ljava/lang/invoke/MethodHandle;
>>> 2: aload_0
>>> 3: getfield #13 // Field
>>> arg$1:Lorg/wildfly/security/WildFlyElytronBaseProvider;
>>> 6: aload_1
>>> 7: checkcast #28 // class
>>> java/security/Provider$Service
>>> 10: invokevirtual #34 // Method
>>> java/lang/invoke/MethodHandle.invokeExact:(Lorg/wildfly/security/WildFlyElytronBaseProvider;Ljava/security/Provider$Service;)V
>>> 13: return
>>>
>>> The scenario is during the assembly phase as part of the
>>> indy resolution the MethodHandle for which the exception
>>> is thrown gets created.
>>> Normally MethodHandle's type gets added in
>>> MethodType::internTable but by the time indy resolution
>>> happens, JVM has already taken
>>> snapshot of the MethodType::internTable through an
>>> upcall to MethodType::createArchivedObjects().
>>> As a result the AOTCache ends up with the MethodType
>>> object which is not in AOTHolder.archivedMethodTypes.
>>>
>>> During the production run, when the jvm invokes the
>>> MethodHandle, it searches for the MethodType
>>> corresponding to the signature passed at the callsite.
>>> As expected, it fails to find it in the
>>> AOTHolder.archivedMethodTypes, so it creates a new
>>> instance of the MethodType.
>>> But Invokers.checkExactType() relies on the
>>> MethodHandle's type to be the same object as the
>>> MethodType object passed as parameter.
>>>
>>> static void checkExactType(MethodHandle mhM,
>>> MethodType expected) {
>>> MethodType targetType = mh.type();
>>> if (targetType != expected)
>>> throw
>>> newWrongMethodTypeException(targetType, expected);
>>> }
>>>
>>> Hence, it throws WrongMethodTypeException though the two
>>> MT objects have the same signature.
>>>
>>> To handle this scenario, I changed the order of indy
>>> resolution and upcall to
>>> MethodType::createArchivedObjects() as:
>>>
>>> diff --git a/src/hotspot/share/cds/metaspaceShared.cpp
>>> b/src/hotspot/share/cds/metaspaceShared.cpp
>>> index df4bcadefa3..457716cac5b 100644
>>> --- a/src/hotspot/share/cds/metaspaceShared.cpp
>>> +++ b/src/hotspot/share/cds/metaspaceShared.cpp
>>> @@ -751,6 +751,20 @@ void
>>> MetaspaceShared::link_shared_classes(bool jcmd_request,
>>> TRAPS) {
>>> if (CDSConfig::is_dumping_final_static_archive()) {
>>> FinalImageRecipes::apply_recipes(CHECK);
>>> }
>>> +
>>> +#if INCLUDE_CDS_JAVA_HEAP
>>> + if (CDSConfig::is_dumping_invokedynamic()) {
>>> + // This makes sure that the MethodType and
>>> MethodTypeForm tables won't be updated
>>> + // concurrently when we are saving their contents
>>> into a side table.
>>> + assert(CDSConfig::allow_only_single_java_thread(),
>>> "Required");
>>> +
>>> + JavaValue result(T_VOID);
>>> + JavaCalls::call_static(&result,
>>> vmClasses::MethodType_klass(),
>>> + vmSymbols::createArchivedObjects(),
>>> + vmSymbols::void_method_signature(),
>>> + CHECK);
>>> + }
>>> +#endif
>>> }
>>> Note that indy resolution happens as part of
>>> FinalImageRecipes::apply_recipes(CHECK) which is now
>>> invoked before the upcall to createArchivedObjects().
>>> With this change I am able to run the application
>>> without any exceptions.
>>> My complete patch can be seen here:
>>> https://github.com/ashu-mehra/leyden/commit/d8f99cce67df1c7b0f7ef8562676df438633a66e
>>> <https://urldefense.com/v3/__https://github.com/ashu-mehra/leyden/commit/d8f99cce67df1c7b0f7ef8562676df438633a66e__;!!ACWV5N9M2RV99hQ!MnS3LSY2PXCCXbHvdyMfR6Nj57XH7Ey7aZuOLmQ__hhE_RhUrKnkzZ0uP8AwLZYcl8lAhhZK3GwoiA$>
>>> I will do more testing with this patch.
>>>
>>> @Ioi Lam <mailto:ioi.lam at oracle.com> do you have any
>>> feedback on this patch.
>>>
>>> Thanks,
>>> - Ashutosh Mehra
>>>
>>>
>>>
>>> On Wed, Sep 11, 2024 at 10:14 AM Ashutosh Mehra
>>> <asmehra at redhat.com> wrote:
>>>
>>> Hi Andrew,
>>> Thanks for sharing the initial investigation.
>>> I have been looking into this and have a few of
>>> things to add to your analysis:
>>>
>>> 1. As you mentioned the classData for the lambda
>>> class WildFlyElytronBaseProvider$$Lambda is null.
>>> The classData is stored in the mirror object of the
>>> InstanceKlass when the class is defined
>>> through JVM_LookupDefineClass.
>>> However, when we create the scratch mirror object
>>> (which get stored in the AOT cache) the classData is
>>> not populated.
>>> See
>>> https://github.com/openjdk/leyden/blob/d23b9f2d5e3523cc547337da59327ed86a6057a3/src/hotspot/share/classfile/javaClasses.cpp#L1128-L1131
>>> <https://urldefense.com/v3/__https://github.com/openjdk/leyden/blob/d23b9f2d5e3523cc547337da59327ed86a6057a3/src/hotspot/share/classfile/javaClasses.cpp*L1128-L1131__;Iw!!ACWV5N9M2RV99hQ!MnS3LSY2PXCCXbHvdyMfR6Nj57XH7Ey7aZuOLmQ__hhE_RhUrKnkzZ0uP8AwLZYcl8lAhhbKjzG3gw$>
>>>
>>> Handle classData; // set to null. Will be
>>> reinitialized at runtime
>>> Handle mirror;
>>> Handle comp_mirror;
>>> allocate_mirror(k, /*is_scratch=*/true,
>>> protection_domain, classData, mirror, comp_mirror,
>>> CHECK);
>>>
>>> So this explains why the call to
>>> classData(caller.lookupClass())returned null.
>>>
>>> 2. In the mainline there is a check
>>> in InnerClassLambdaMetafactory.java for the
>>> particular code pattern used by the application.
>>> If this code pattern is found then the lambda proxy
>>> class is not included in the CDS archive.
>>> See
>>> https://github.com/openjdk/leyden/blob/d23b9f2d5e3523cc547337da59327ed86a6057a3/src/java.base/share/classes/java/lang/invoke/InnerClassLambdaMetafactory.java#L163-L170
>>> <https://urldefense.com/v3/__https://github.com/openjdk/leyden/blob/d23b9f2d5e3523cc547337da59327ed86a6057a3/src/java.base/share/classes/java/lang/invoke/InnerClassLambdaMetafactory.java*L163-L170__;Iw!!ACWV5N9M2RV99hQ!MnS3LSY2PXCCXbHvdyMfR6Nj57XH7Ey7aZuOLmQ__hhE_RhUrKnkzZ0uP8AwLZYcl8lAhhZl2S9tQg$>
>>> and
>>> https://github.com/openjdk/leyden/blob/d23b9f2d5e3523cc547337da59327ed86a6057a3/src/java.base/share/classes/java/lang/invoke/InnerClassLambdaMetafactory.java#L246
>>> <https://urldefense.com/v3/__https://github.com/openjdk/leyden/blob/d23b9f2d5e3523cc547337da59327ed86a6057a3/src/java.base/share/classes/java/lang/invoke/InnerClassLambdaMetafactory.java*L246__;Iw!!ACWV5N9M2RV99hQ!MnS3LSY2PXCCXbHvdyMfR6Nj57XH7Ey7aZuOLmQ__hhE_RhUrKnkzZ0uP8AwLZYcl8lAhhYsI3Xx0g$>
>>>
>>> // If the target class invokes a protected
>>> method inherited from a
>>> // superclass in a different package, or
>>> does 'invokespecial', the
>>> // lambda class has no access to the
>>> resolved method, or does
>>> // 'invokestatic' on a hidden class which
>>> cannot be resolved by name.
>>> // Instead, we need to pass the live
>>> implementation method handle to
>>> // the proxy class to invoke directly.
>>> (javac prefers to avoid this
>>> // situation by generating bridges in the
>>> target class)
>>> useImplMethodHandle =
>>> (Modifier.isProtected(implInfo.getModifiers()) &&
>>> !VerifyAccess.isSamePackage(targetClass,
>>> implInfo.getDeclaringClass())) ||
>>> implKind == MethodHandleInfo.REF_invokeSpecial ||
>>> implKind == MethodHandleInfo.REF_invokeStatic &&
>>> implClass.isHidden();
>>>
>>> In premain lambda proxy classes get included in the
>>> AOT cache as a result of indy resolution and that
>>> mechanism doesn't have this kind of check.
>>>
>>> 3. For the null classData problem mentioned above, I
>>> tried to fix it by storing classData in the scratch
>>> mirror using the following patch:
>>>
>>> diff --git
>>> a/src/hotspot/share/classfile/javaClasses.cpp
>>> b/src/hotspot/share/classfile/javaClasses.cpp
>>> index bd8141adbcc..41766e98093 100644
>>> --- a/src/hotspot/share/classfile/javaClasses.cpp
>>> +++ b/src/hotspot/share/classfile/javaClasses.cpp
>>> @@ -1094,9 +1094,9 @@ void
>>> java_lang_Class::create_mirror(Klass* k, Handle
>>> class_loader,
>>> }
>>> if (CDSConfig::is_dumping_heap()) {
>>> if (CDSConfig::is_dumping_protection_domains()) {
>>> - create_scratch_mirror(k, protection_domain,
>>> CHECK);
>>> + create_scratch_mirror(k, protection_domain,
>>> classData, CHECK);
>>> } else {
>>> - create_scratch_mirror(k, Handle() /* null
>>> protection_domain*/, CHECK);
>>> + create_scratch_mirror(k, Handle() /* null
>>> protection_domain*/, classData, CHECK);
>>> }
>>> }
>>> } else {
>>> @@ -1117,7 +1117,7 @@ void
>>> java_lang_Class::create_mirror(Klass* k, Handle
>>> class_loader,
>>> // Note: we archive the "scratch mirror" instead of
>>> k->java_mirror(), because the
>>> // latter may contain dumptime-specific information
>>> that cannot be archived
>>> // (e.g., ClassLoaderData*, or static fields that
>>> are modified by Java code execution).
>>> -void java_lang_Class::create_scratch_mirror(Klass*
>>> k, Handle protection_domain, TRAPS) {
>>> +void java_lang_Class::create_scratch_mirror(Klass*
>>> k, Handle protection_domain, Handle classData, TRAPS) {
>>> if (k->class_loader() != nullptr &&
>>> k->class_loader() !=
>>> SystemDictionary::java_platform_loader() &&
>>> k->class_loader() !=
>>> SystemDictionary::java_system_loader()) {
>>> @@ -1125,9 +1125,11 @@ void
>>> java_lang_Class::create_scratch_mirror(Klass* k,
>>> Handle protection_domain,
>>> return;
>>> }
>>>
>>> - Handle classData; // set to null. Will be
>>> reinitialized at runtime
>>> + //Handle classData; // set to null. Will be
>>> reinitialized at runtime
>>> Handle mirror;
>>> Handle comp_mirror;
>>> allocate_mirror(k, /*is_scratch=*/true,
>>> protection_domain, classData, mirror, comp_mirror,
>>> CHECK);
>>>
>>> if (comp_mirror() != nullptr) {
>>> diff --git
>>> a/src/hotspot/share/classfile/javaClasses.hpp
>>> b/src/hotspot/share/classfile/javaClasses.hpp
>>> index bc49a0861a7..7ec2a2556dd 100644
>>> --- a/src/hotspot/share/classfile/javaClasses.hpp
>>> +++ b/src/hotspot/share/classfile/javaClasses.hpp
>>> @@ -263,7 +263,7 @@ class java_lang_Class : AllStatic {
>>>
>>> // Archiving
>>> static void serialize_offsets(SerializeClosure*
>>> f) NOT_CDS_RETURN;
>>> - static void create_scratch_mirror(Klass* k,
>>> Handle protection_domain, TRAPS)
>>> NOT_CDS_JAVA_HEAP_RETURN;
>>> + static void create_scratch_mirror(Klass* k,
>>> Handle protection_domain, Handle classData, TRAPS)
>>> NOT_CDS_JAVA_HEAP_RETURN;
>>> static bool restore_archived_mirror(Klass *k,
>>> Handle class_loader, Handle module,
>>> Handle protection_domain,
>>> TRAPS) NOT_CDS_JAVA_HEAP_RETURN_(false);
>>>
>>> But this resulted in a different exception:
>>>
>>> Exception in thread "main"
>>> java.lang.ExceptionInInitializerError
>>> at com.redhat.leyden.Main.main(Main.java:7)
>>> Caused by:
>>> java.lang.invoke.WrongMethodTypeException: handle's
>>> method type (WildFlyElytronBaseProvider,Service)void
>>> but found (WildFlyElytronBaseProvider,Service)void
>>> at
>>> java.base/java.lang.invoke.Invokers.newWrongMethodTypeException(Invokers.java:521)
>>> at
>>> java.base/java.lang.invoke.Invokers.checkExactType(Invokers.java:530)
>>> at
>>> java.base/java.lang.invoke.Invokers$Holder.invokeExact_MT(Invokers$Holder)
>>> at
>>> org.wildfly.security.WildFlyElytronBaseProvider$$Lambda/0x80000000c.accept(Unknown
>>> Source)
>>> at
>>> org.wildfly.security.WildFlyElytronBaseProvider.putMakedPasswordImplementations(WildFlyElytronBaseProvider.java:112)
>>> at
>>> org.wildfly.security.WildFlyElytronBaseProvider.putPasswordImplementations(WildFlyElytronBaseProvider.java:107)
>>> at
>>> org.wildfly.security.password.WildFlyElytronPasswordProvider.<init>(WildFlyElytronPasswordProvider.java:43)
>>> at
>>> org.wildfly.security.password.WildFlyElytronPasswordProvider.<clinit>(WildFlyElytronPasswordProvider.java:36)
>>> ... 1 more
>>>
>>> The exception message is strange because the
>>> handle's method type and the expected type are both
>>> symbolically the same.
>>> I am debugging this exception at the moment.
>>> Thanks,
>>> - Ashutosh Mehra
>>>
>>>
>>> On Wed, Sep 11, 2024 at 6:03 AM Andrew Dinn
>>> <adinn at redhat.com> wrote:
>>>
>>> Oops, sorry, I debugged this a few days ago!
>>> Correction to a few details:
>>>
>>> On 11/09/2024 10:39, Andrew Dinn wrote:
>>> > A crash due to an NPE was observed in the
>>> Infinispan (Data Grid) server
>>> > app when deployed using the Leyden EA. The
>>> crash still manifests with
>>> > the latest premain code. The crash happens
>>> below an application call
>>> > which employs a method reference as argument
>>> >
>>> >
>>> putMakedPasswordImplementations(this::putService,
>>> this);
>>>
>>> The called method in turn calls consumer.accept
>>>
>>> consumer.accept(new Service(provider,
>>> PASSWORD_FACTORY_TYPE, algorithm,
>>> "org.wildfly.security.password.impl.PasswordFactorySpiImpl",
>>> emptyList,
>>> emptyMap));
>>>
>>> which enters enters
>>> MethodHandleNative::linkDynamicConstant()
>>>
>>> > Debugging shows that the call to
>>> linkDynamicConstant() returns null.
>>> >
>>> > A simple reproducer for the problem is
>>> available as a maven project on
>>> > github:
>>> >
>>> >
>>> https://github.com/tristantarrant/elytron-leyden
>>> <https://urldefense.com/v3/__https://github.com/tristantarrant/elytron-leyden__;!!ACWV5N9M2RV99hQ!MnS3LSY2PXCCXbHvdyMfR6Nj57XH7Ey7aZuOLmQ__hhE_RhUrKnkzZ0uP8AwLZYcl8lAhhZaZr1akQ$>
>>> >
>>> > The ReadMe provides an explanation of how to
>>> reproduce the problem. I
>>> > did so and the debugged to find out some of
>>> the details of what is
>>> > happening (see below) but did not fully
>>> clarify the problem. Help from
>>> > someone more conversant with the ins and outs
>>> of method handle
>>> > bootstraps in premain would be welcome.
>>> Details follow.
>>> >
>>> > regards,
>>> >
>>> >
>>> > Andrew Dinn
>>> > -----------
>>> >
>>> > I downloaded the git repo and attached the
>>> Java sources using Maven command
>>> >
>>> > $ mvn dependency:sources
>>> >
>>> > Having manifested the crash by following the
>>> instructions in the README
>>> > I reran the leyden JVM under gdb using the
>>> following commands to enable
>>> > Java debugging
>>> >
>>> > $ gdb ${LEYDEN_HOME}/bin/java
>>> > (gdb) cd /path/to/mvn/project
>>> > (gdb) run
>>> >
>>> -agentlib:jdwp=transport=dt_socket,server=y,suspend=y,address=5005
>>>
>>> > -classpath
>>> >
>>> /home/adinn/redhat/openjdk/infinispan/elytron-leyden/base/target/elytron-leyden-base-0.0.1-SNAPSHOT.jar:/home/adinn/.m2/repository/org/wildfly/security/wildfly-elytron-credential/2.5.1.
>>> <https://urldefense.com/v3/__http://2.5.1.__;!!ACWV5N9M2RV99hQ!MnS3LSY2PXCCXbHvdyMfR6Nj57XH7Ey7aZuOLmQ__hhE_RhUrKnkzZ0uP8AwLZYcl8lAhhauJ-RjcQ$>Final/wildfly-elytron-credential-2.5.1.Final.jar:/home/adinn/.m2/repository/org/wildfly/security/wildfly-elytron-base/2.5.1.Final/wildfly-elytron-base-2.5.1.Final.jar
>>> -XX:CacheDataStore=elytron.aot
>>> com.redhat.leyden.Main
>>> >
>>> > The problem manifests at
>>> WildflyElytronBaseProvider.java:112 in method
>>> >
>>> WildflyElytronBaseProvider::putMakedPasswordImplementations
>>>
>>> static void
>>> putMakedPasswordImplementations(Consumer<Service>
>>> consumer, Provider provider) {
>>> for (String algorithm :
>>> MASKED_ALGORITHMS) {
>>> consumer.accept(new Service(provider,
>>> PASSWORD_FACTORY_TYPE, algorithm,
>>> "org.wildfly.security.password.impl.PasswordFactorySpiImpl",
>>> emptyList,
>>> emptyMap)); <== NPE under this call
>>> }
>>>
>>>
>>> > The source code for this method can be found
>>> in the following source jar
>>> >
>>> >
>>> >
>>> ${M2_REPO}/org/wildfly/security/wildfly-elytron-base/2.5.1.Final/wildfly-elytron-base-2.5.1.Final-sources.jar
>>> >
>>> > (where M2_REPO will normally be ~/.m2/repository)
>>> >
>>> > Stepping into accept eventually enters
>>> MethodHandleNative::linkDynamicConstant
>>> > which in turn enters into
>>> ConstantBootstraps.makeConstant(). The caller
>>> > Class at this point is a lambda class which
>>> prints as
>>> >
>>> org.wildfly.security.WildflyElytronBaseProvider$$Lambda/0x800000000c
>>> >
>>> > Several steps further the code enters
>>> BootstrapMethodInvoker::invoke
>>> > (below the app method call but via 3 hidden
>>> frames) with bootstrapMethod
>>> > bound to a DirectMethodHandle. After several
>>> more steps this enters
>>> > DirectMethodHandle$Holder.invokeStatic which
>>> in turn calls
>>> > MethodHandles::classData(Lookup,String,Class).
>>> >
>>> > At this point caller is a MethodHandleLookup
>>> for the lambda class
>>> > Lambda/0x800000000c mentioned above. The
>>> following call
>>> >
>>> > Object classdata =
>>> classData(caller.lookupClass());
>>> >
>>> > returns null to
>>> DirectMethodHandle$Holder.invokeStatic which
>>> pops the
>>> > same result back out to
>>> BootstrapMethodInvoker::invoke at line 90
>>> >
>>> > if (type instanceof Class<?> c) {
>>> > result =
>>> bootstrapMethod.invoke(caller, name, c);
>>> > <== null
>>> >
>>> > This null result pops back out as the value
>>> for the call to
>>> > BootstrapMethodInvoker.invoke(),
>>> ConstantBootstraps.makeConstant() and
>>> > MethodHandleNative::linkDynamicConstant().
>>> >
>>>
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