Eclipse aborts on WebKitGTK 2.53.90+ — WTF main-thread assertion cannot be satisfied by a JVM embedder

[mark97753]

Important

If you are reporting a crash on Linux, please check if webkit is mentioned in the crash file.
If yes, please try to set WEBKIT_DISABLE_COMPOSITING_MODE=1 and/or WEBKIT_DISABLE_DMABUF_RENDERER=1 environment variables.
If they prevent crashes, don't report the bug please, it is already known as #843

Describe the bug
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To Reproduce
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(or)
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Expected behavior
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Environment:

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• • Windows
• • Linux
• • macOS

2. Additional OS info (e.g. OS version, Linux Desktop, etc)

3. JRE/JDK version

Version since
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Workaround (or) Additional context
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[mark97753]

Reproduces standalone with the snippet above — no Eclipse, no plugins, no workspace:

$ /opt/jdk-26.0.2.1/bin/java -cp org.eclipse.swt.gtk.linux.x86_64_3.135.0.v20260819-1952.jar BrowserCrash.java
Aborted (core dumped)

Stack trace of thread 222647:
#0 __pthread_kill_implementation (libc.so.6)
#1 raise (libc.so.6)
#2 abort (libc.so.6)
#3 WTFCrashWithInfo (libjavascriptcoregtk-4.1.so.0)
#4 WTF::initializeMainThread()::$_0::operator()() const (libjavascriptcoregtk-4.1.so.0)
#5 __pthread_once_slow (libc.so.6)
#6 pthread_once@GLIBC_2.2.5 (libc.so.6)
#7 WTF::initializeMainThread() (libjavascriptcoregtk-4.1.so.0)
#8 WebKit::webkitInitialize() (libwebkit2gtk-4.1.so.0)
#9 __pthread_once_slow (libc.so.6)
#10 pthread_once@GLIBC_2.2.5 (libc.so.6)
#11 webkit_web_context_class_intern_init (libwebkit2gtk-4.1.so.0)
#12 g_type_class_get (libgobject-2.0.so.0)
#13 g_object_new_with_properties (libgobject-2.0.so.0)
#14 g_object_new (libgobject-2.0.so.0)
#15 createDefaultWebContext (libwebkit2gtk-4.1.so.0)
#16 g_once_impl (libglib-2.0.so.0)
#17 Java_org_eclipse_swt_internal_webkit_WebKitGTK_webkit_1web_1context_1get_1default
(libswt-webkit-gtk-4974r10.so)

SWT 3.135.0.v20260819-1952, JDK 26.0.2.1, webkitgtk4.1-2.53.92-1.fc45,
Fedora 45, KDE Plasma on Wayland.

[mark97753]

To be clear about the distro state: Fedora 45 is still pre-release (GA is
20 October 2026) and webkitgtk 2.53.9x is a development snapshot, so this is
not yet affecting users on a shipped Fedora.

It isn't going away on its own, though — the assertion has been present and
unchanged across 2.53.90, .91 and .92, and it's still there in the released
2.53.92 source. Fedora will ship one of these at GA.

[akurtakov]

Adding https://bugs.webkit.org/show_bug.cgi?id=322394 which seems to be upstream issue for the problem.