RFR: 8335469: [XWayland] crash when an AWT ScreenCast session overlaps with an FX ScreenCast session

Alexander Zvegintsev azvegint at openjdk.org
Fri Nov 15 02:10:51 UTC 2024


This is the FX counterpart of the [openjdk/jdk/pull/22131](https://github.com/openjdk/jdk/pull/22131) / `b.`(aka crash prevention part)

It does not crash without the [openjdk/jdk/pull/22131](https://github.com/openjdk/jdk/pull/22131) / `a.` part.

The crash prevention part  is the same for the JDK and JavaFX, except that this PR includes a test.

---- 

Internally the ScreenCast session keeps open for 2s (both JDK and JFX, and their implementations are almost identical).
This is to reduce overhead in case of frequent consecutive screen captures.

When we perform a [cleanup](https://github.com/openjdk/jdk/blob/db56266ad164b4ecae59451dc0a832097dbfbd8e/src/java.desktop/unix/native/libawt_xawt/awt/screencast_pipewire.c#L91) to close the session, we internally call [`pw_deinit`](https://docs.pipewire.org/group__pw__pipewire.html#gafa6045cd7391b467af4575c6752d6c4e).

It becomes a problem if these sessions overlap in time, so that the second session cleanup crashes when it tries to call pipewire functions without initializing the pipewire system by  [`pw_init`](https://docs.pipewire.org/group__pw__pipewire.html#ga06c879b2d800579f4724109054368d99) (please note that `This function can be called multiple times.`).

So the solution is not to call `pw_deinit` because we don't really need it, and it needs to be applied to both the JDK and JavaFX.

[jdk commit](https://github.com/openjdk/jdk/pull/22131/commits/19956fda202269e92ec70670bc88c8d3c7accf73) / [jfx commit](https://github.com/openjdk/jfx/pull/1639/commits/dba8a8871a38831d0a0da697a2be41f0c240c8f0)

----

The newly introduced test is disabled for now(as part  of [JDK-8335470](https://bugs.openjdk.org/browse/JDK-8335470)), because it requires the fix on both the JavaFX and JDK sides.
For the same reason `tests/system/src/test/java/test/robot/javafx/embed/swing/SwingNodeJDialogTest.java` and `tests/system/src/test/java/test/robot/javafx/scene/SRGBTest.java` are not enabled back.
But if the JDK and JavaFX have the fixes, everything works fine.
Testing in other different scenarios also looks good.

-------------

Commit messages:
 - 8335469: [XWayland] crash when an AWT ScreenCast session overlaps with an FX ScreenCast session

Changes: https://git.openjdk.org/jfx/pull/1639/files
  Webrev: https://webrevs.openjdk.org/?repo=jfx&pr=1639&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8335469
  Stats: 156 lines in 3 files changed: 150 ins; 6 del; 0 mod
  Patch: https://git.openjdk.org/jfx/pull/1639.diff
  Fetch: git fetch https://git.openjdk.org/jfx.git pull/1639/head:pull/1639

PR: https://git.openjdk.org/jfx/pull/1639


More information about the openjfx-dev mailing list