RFR: 8370176: Mixed mode jhsdb jstack cannot unwind call stack with -Xcomp [v12]

[Kevin Walls]

On Sat, 1 Nov 2025 03:20:49 GMT, Yasumasa Suenaga <ysuenaga at openjdk.org> wrote:

>> `jhsdb jstack --mixed` would not work when attaches to the process runs with `-Xcomp`.
>> 
>> It has been reported by @pchilano in #27728. You can reproduce the problem with [Test.java (attached JBS)](https://bugs.openjdk.org/secure/attachment/116551/Test.java). You can see following stack.
>> 
>> 
>> ----------------- 646689 -----------------
>> "Thread-0" #24 prio=5 tid=0x00007f1cec18c890 nid=646689 waiting on condition [0x00007f1cd0158000]
>>    java.lang.Thread.State: TIMED_WAITING (sleeping)
>>    JavaThread state: _thread_blocked
>> 0x00007f1cf3b7f462 __syscall_cancel_arch + 0x32
>> 0x00007f1cf3b7375c __internal_syscall_cancel + 0x5c
>> 0x00007f1cf3b766a8 ___pthread_cond_timedwait + 0x178
>> 0x00007f1cf270e1e9 PlatformEvent::park_nanos(long) + 0x119
>> 0x00007f1cf2005f4c JavaThread::sleep_nanos(long) + 0xfc
>> 0x00007f1cf218789f JVM_SleepNanos + 0x28f
>> 0x00007f1cdb95f299 java.lang.Thread.sleepNanos0(long) + 0x99 (Native method)
>> 
>> 
>> `Thread.sleepNanos0` is the bottom stack, but actually it has more call frames. You can see them with `-XX:+PreserveFramePointer`.
>> 
>> 
>> ----------------- 646841 -----------------
>> "Thread-0" #24 prio=5 tid=0x00007f4a0018c9e0 nid=646841 waiting on condition [0x00007f49e4fd7000]
>>    java.lang.Thread.State: TIMED_WAITING (sleeping)
>>    JavaThread state: _thread_blocked
>> 0x00007f4a0aa29462 __syscall_cancel_arch + 0x32
>> 0x00007f4a0aa1d75c __internal_syscall_cancel + 0x5c
>> 0x00007f4a0aa206a8 ___pthread_cond_timedwait + 0x178
>> 0x00007f4a0970e1e9 PlatformEvent::park_nanos(long) + 0x119
>> 0x00007f4a09005f4c JavaThread::sleep_nanos(long) + 0xfc
>> 0x00007f4a0918789f JVM_SleepNanos + 0x28f
>> 0x00007f49ef961099 java.lang.Thread.sleepNanos0(long) + 0x99 (Native method)
>> 0x00007f49e7f477b4 * java.lang.Thread.sleepNanos(long) bci:33 line:509 (Compiled frame)
>> 0x00007f49e7f41a64 * java.lang.Thread.sleep(long) bci:25 line:540 (Compiled frame)
>> 0x00007f49e7f4037c * Test.run() bci:3 line:6 (Compiled frame)
>> 0x00007f49ef943328 * java.lang.Thread.runWith(java.lang.Object, java.lang.Runnable) bci:5 line:1487 (Compiled frame)
>>                         * java.lang.Thread.run() bci:19 line:1474 (Compiled frame)
>> 0x00007f49ef3385fd <StubRoutines (initial stubs)>
>> 0x00007f4a08fc247e JavaCalls::call_helper(JavaValue*, methodHandle const&, JavaCallArguments*, JavaThread*) + 0x4ce
>> 0x00007f4a08fc2bb3 JavaCalls::call_virtual(JavaValue*, Klass*, Symbol*, Symbol*, JavaCallArguments*, JavaThread*) + 0x2d3
>> 0x00007f4a08fc31bb JavaCalls::call_virtu...
>
> Yasumasa Suenaga has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains 16 commits:
> 
>  - Merge branch 'master' into jhsdb-jstack-bp
>  - Improve comments in isValidFrame method
>  - Use stderrShouldBeEmptyIgnoreVMWarnings
>  - TestJhsdbJstackMixedWithXComp.java should be run on Linux AMD64 only
>  - Respect RSP to parse DWARF
>  - Revert testcase changes
>  - Fix imports
>  - Update testcase
>  - Update testcase
>  - Add glibc version check to TestJhsdbJstackMixedWithXComp.java
>  - ... and 6 more: https://git.openjdk.org/jdk/compare/d2260236...eb2f0ab0

Thanks, spent quite a while going over this yesterday and think it's good.
Yes was waiting for the conflict with 8369994, that looks like it merged in OK. 8-)

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

Marked as reviewed by kevinw (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/27885#pullrequestreview-3407206806