`JVM_MoreStackWalk` has a bug that always assumes that the Java frame stream is currently at the frame decoded in the last patch and so always advances to the next frame before filling in the new batch of stack frame. However `JVM_MoreStackWalk` may return 0. The library will set the continuation to its parent. It then call `JVM_MoreStackWalk` to continue the stack walking but the last decoded frame has already been advanced. The Java frame stream is already at the top frame of the parent continuation. . The current implementation skips "Continuation::yield0" mistakenly. This only happens with `-XX:+ShowHiddenFrames` or `StackWalker.Option.SHOW_HIDDEN_FRAMES`.
The fix is to pass the number of frames decoded in the last batch to `JVM_MoreStackWalk` so that the VM will determine if the current frame should be skipped or not. `test/jdk/jdk/internal/vm/Continuation/Scoped.java` test now correctly checks the expected result where "yield0" exists between "enter" and "run" frames. ------------- Commit messages: - 8316456: StackWalker may skip Continuation::yield0 frame mistakenly Changes: https://git.openjdk.org/jdk/pull/15804/files Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=15804&range=00 Issue: https://bugs.openjdk.org/browse/JDK-8316456 Stats: 128 lines in 7 files changed: 36 ins; 11 del; 81 mod Patch: https://git.openjdk.org/jdk/pull/15804.diff Fetch: git fetch https://git.openjdk.org/jdk.git pull/15804/head:pull/15804 PR: https://git.openjdk.org/jdk/pull/15804
