RFR: 8370176: Mixed mode jhsdb jstack cannot unwind call stack with -Xcomp [v2]

[Fei Yang]

On Tue, 21 Oct 2025 05:44:00 GMT, Yasumasa Suenaga <ysuenaga at openjdk.org> wrote:

>> test/hotspot/jtreg/serviceability/sa/TestJhsdbJstackMixedWithXComp.java line 40:
>> 
>>> 38:  * @bug 8370176
>>> 39:  * @requires vm.hasSA
>>> 40:  * @requires os.family == "linux"
>> 
>> Do Windows and OSX have a similar problem that should be fixed also?
>
> This problem is in mixed mode (`PStack`) only, thus we need to skip OSX because [you mentioned](https://github.com/openjdk/jdk/pull/27728#issuecomment-3392919979) mixed mode is not supported on OSX.
> 
> In Windows, I'm not sure, but I guess we need to consider `UNWIND_INFO` to unwind call frames correctly like DWARF in Linux, however it hasn't done yet. Thus we can think mixed mode is not supported in Windows too, so I didn't add Windows here.
> https://learn.microsoft.com/cpp/build/exception-handling-x64
> 
> Actually I could not see all of stacks as following in mixed mode. It works in normal mode (without `--mixed`) of course. (I tested it on Windows 11 x64, upstream JDK built by VS 2022)
> 
> ----------------- 13 -----------------
> "Reference Handler" #15 daemon prio=10 tid=0x00000207280b9f70 nid=12684 waiting on condition [0x000000aaf6aff000]
>    java.lang.Thread.State: RUNNABLE
>    JavaThread state: _thread_blocked
> 0x00007fffa6b45844      ntdll!NtWaitForAlertByThreadId + 0x14
> 0x00000000ffffffff              ????????

Mind you that this new test seems to fail even on linux systems without pstack. This is happening on both of my AMD64 machine running Debian 12 and ARM64 machine running Ubuntu 22.04.4.

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PR Review Comment: https://git.openjdk.org/jdk/pull/27885#discussion_r2453813619