JDK-8242361: Web View crash with data urls: further information

Sat Nov 21 21:42:53 UTC 2020

Hi,

I found JDK-8242361, because I observed a segfault when running a web
application of medium complexity in a WebView, that was embedded in
NetBeans.

Before you say it: NetBeans loads the openjfx jars via the classpath.
I'm aware that OpenJFX should be loaded as a named module, but that is
far from trivial to realize inside the environment, so at this point in
time I'd like to try to fix the problem at hand.

I managed to get a core dump from the crash and running it through gdb
with debug symbols I get:

============================================================

#0  __GI_raise (sig=sig at entry=6) at ../sysdeps/unix/sysv/linux/raise.c:49
#1  0x00007f93c40e5864 in __GI_abort () at abort.c:79
#2  0x00007f93c30603e7 in os::abort(bool, void*, void const*) (dump_core=<optimized out>, siginfo=<optimized out>, context=<optimized out>) at ./src/hotspot/os/linux/os_linux.cpp:1503
#3  0x00007f93c3c58798 in VMError::report_and_die(int, char const*, char const*, __va_list_tag*, Thread*, unsigned char*, void*, void*, char const*, int, unsigned long)
    (id=<optimized out>, message=message at entry=0x0, detail_fmt=<optimized out>, detail_args=detail_args at entry=0x7f9189ffe368, thread=thread at entry=0x7f925c314000, pc=pc at entry=0x7f93c3348804 <AccessInternal::PostRuntimeDispatch<G1BarrierSet::AccessBarrier<1097844ul, G1BarrierSet>, (AccessInternal::BarrierType)2, 1097844ul>::oop_access_barrier(void*)+4> "H\213\a\303\017\037\204", siginfo=0x7f9189ffe6f0, context=0x7f9189ffe5c0, filename=<optimized out>, lineno=0, size=0) at ./src/hotspot/share/utilities/vmError.cpp:1603
#4  0x00007f93c3c590cf in VMError::report_and_die(Thread*, unsigned int, unsigned char*, void*, void*, char const*, ...)
    (thread=thread at entry=0x7f925c314000, sig=sig at entry=11, pc=pc at entry=0x7f93c3348804 <AccessInternal::PostRuntimeDispatch<G1BarrierSet::AccessBarrier<1097844ul, G1BarrierSet>, (AccessInternal::BarrierType)2, 1097844ul>::oop_access_barrier(void*)+4> "H\213\a\303\017\037\204", siginfo=siginfo at entry=0x7f9189ffe6f0, context=context at entry=0x7f9189ffe5c0, detail_fmt=detail_fmt at entry=0x7f93c3d1348e "%s") at ./src/hotspot/share/utilities/vmError.cpp:1270
#5  0x00007f93c3c59102 in VMError::report_and_die(Thread*, unsigned int, unsigned char*, void*, void*)
    (thread=thread at entry=0x7f925c314000, sig=sig at entry=11, pc=pc at entry=0x7f93c3348804 <AccessInternal::PostRuntimeDispatch<G1BarrierSet::AccessBarrier<1097844ul, G1BarrierSet>, (AccessInternal::BarrierType)2, 1097844ul>::oop_access_barrier(void*)+4> "H\213\a\303\017\037\204", siginfo=siginfo at entry=0x7f9189ffe6f0, context=context at entry=0x7f9189ffe5c0)
    at ./src/hotspot/share/utilities/vmError.cpp:1276
#6  0x00007f93c39b0d02 in JVM_handle_linux_signal(int, siginfo_t*, void*, int)
    (sig=sig at entry=11, info=info at entry=0x7f9189ffe6f0, ucVoid=ucVoid at entry=0x7f9189ffe5c0, abort_if_unrecognized=abort_if_unrecognized at entry=1) at ./src/hotspot/os_cpu/linux_x86/os_linux_x86.cpp:616
#7  0x00007f93c39a3fdc in signalHandler(int, siginfo_t*, void*) (sig=11, info=0x7f9189ffe6f0, uc=0x7f9189ffe5c0) at ./src/hotspot/os/linux/os_linux.cpp:4693
#8  0x00007f93c4100950 in <signal handler called> () at /lib/x86_64-linux-gnu/libc.so.6
#9  AccessInternal::PostRuntimeDispatch<G1BarrierSet::AccessBarrier<1097844ul, G1BarrierSet>, (AccessInternal::BarrierType)2, 1097844ul>::oop_access_barrier(void*) (addr=0x0)
    at ./src/hotspot/share/gc/g1/g1BarrierSet.inline.hpp:66
#10 0x00007f93c36b0073 in AccessInternal::RuntimeDispatch<1097812ul, oopDesc*, (AccessInternal::BarrierType)2>::load(void*) (addr=0x7f91cd491060) at ./src/hotspot/share/oops/accessBackend.hpp:1325
#11 AccessInternal::PreRuntimeDispatch::load<1097812ul, oopDesc*>(void*) (addr=0x7f91cd491060) at ./src/hotspot/share/oops/accessBackend.hpp:779
#12 AccessInternal::load_reduce_types<1097812ul, oopDesc*>(oopDesc**) (addr=0x7f91cd491060) at ./src/hotspot/share/oops/accessBackend.hpp:1110
#13 AccessInternal::load<1048580ul, oopDesc*, oopDesc*>(oopDesc**) (addr=0x7f91cd491060) at ./src/hotspot/share/oops/accessBackend.hpp:1211
#14 AccessInternal::OopLoadProxy<oopDesc*, 1048576ul>::operator oopDesc*() (this=<optimized out>) at ./src/hotspot/share/oops/accessBackend.hpp:1326
#15 JNIHandles::resolve_impl<0ul, false>(_jobject*) (handle=0x7f91cd491060) at ./src/hotspot/share/runtime/jniHandles.inline.hpp:60
#16 JNIHandles::resolve_non_null(_jobject*) (handle=0x7f91cd491060) at ./src/hotspot/share/runtime/jniHandles.inline.hpp:92
#17 get_method_id(jclass, char const*, char const*, bool, Thread*, JNIEnv*)
    (clazz=clazz at entry=0x0, name_str=name_str at entry=0x7f915c3d3e8a "fwkScheduleDispatchFunctions", sig=sig at entry=0x7f915c396304 "()V", is_static=is_static at entry=true, __the_thread__=__the_thread__ at entry=0x7f925c314000, env=<optimized out>) at ./src/hotspot/share/prims/jni.cpp:1336
#18 0x00007f93c36b040b in jni_GetStaticMethodID(JNIEnv*, jclass, char const*, char const*)
    (env=<optimized out>, clazz=0x0, name=0x7f915c3d3e8a "fwkScheduleDispatchFunctions", sig=0x7f915c396304 "()V") at ./src/hotspot/share/prims/jni.cpp:1382
#19 0x00007f915c0869e6 in WTF::scheduleDispatchFunctionsOnMainThread() () at /home/matthias/.openjfx/cache/13/libjfxwebkit.so
#20 0x00007f915b2a745b in WTF::Function<void ()>::CallableWrapper<WebCore::DataURLDecoder::decode(WTF::URL const&, WebCore::DataURLDecoder::ScheduleContext const&, WTF::Function<void (WTF::Optional<WebCore::DataURLDecoder::Result>)>&&)::{lambda()#1}>::call() () at /home/matthias/.openjfx/cache/13/libjfxwebkit.so
#21 0x00007f915c089150 in WTF::Function<void ()>::CallableWrapper<WTF::WorkQueue::dispatch(WTF::Function<void ()>&&)::{lambda()#1}>::call() () at /home/matthias/.openjfx/cache/13/libjfxwebkit.so
#22 0x00007f915c02215b in WTF::RunLoop::performWork() () at /home/matthias/.openjfx/cache/13/libjfxwebkit.so
#23 0x00007f915c088190 in WTF::RunLoop::runImpl(WTF::RunLoop::RunMode) () at /home/matthias/.openjfx/cache/13/libjfxwebkit.so
#24 0x00007f915c023867 in WTF::Thread::entryPoint(WTF::Thread::NewThreadContext*) () at /home/matthias/.openjfx/cache/13/libjfxwebkit.so
#25 0x00007f915c08a00d in WTF::wtfThreadEntryPoint(void*) () at /home/matthias/.openjfx/cache/13/libjfxwebkit.so
#26 0x00007f93c4083590 in start_thread (arg=0x7f9189fff640) at pthread_create.c:463
#27 0x00007f93c41d8223 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

============================================================

What I also found is, that this is not a general problem of the WebView
on netbeans. I inserted seveal printf statements into the
MainThreadJava.cpp and JavaEnv.h files and found, that there are
several successful calls to isMainThread, but if fails for
scheduleDispatchFunctionsOnMainThread.

What I observe is, that the jclasses and jmethodID are resolved on each
invocation. The few times I work with JNI, the correspoding libraries
resolve the classids and methods at load time once and cache the
results for the lifetime of the library. Wouldn't this also be an
option for OpenJFX? From my observation, the jclasses can be found,
just not for the schedule.

Greetings

Matthias