RFR: 8377947: Test serviceability/sa/TestJhsdbJstackMixedCore.java failed on linux-x64

[Chris Plummer]

On Wed, 18 Feb 2026 06:50:55 GMT, Yasumasa Suenaga <ysuenaga at openjdk.org> wrote:

> This PR is extracted from #29731 .
> 
> We saw following mixed jstack in TestJhsdbJstackMixedCore.java and then it failed due to unsatisfied condition.
> 
> 
> ----------------- 3258804 -----------------
> "main" #3 prio=5 tid=0x00007f497802e450 nid=3258804 runnable [0x00007f4982c74000]
>    java.lang.Thread.State: RUNNABLE
>    JavaThread state: _thread_in_native
> 0x00007f49826dc5ef __GI_raise + 0x10f
> 0x00007f49826afe65 __GI_abort + 0x127
> 0x00007f497fdec90f os::abort(bool, void const*, void const*) [clone .cold] + 0x4
> 0x00007f498175d582 VMError::report_and_die(int, char const*, char const*, __va_list_tag*, Thread*, unsigned char*, void const*, void const*, char const*, int, unsigned long) + 0x6f2
> 0x00007f498072e3c0 report_vm_error(char const*, int, char const*, char const*, ...) + 0x100
> 0x00007f497fe5bb5f CompressedKlassPointers::decode_not_null(unsigned int) + 0x22f
> 0x00007f4982c72010 ????????
> 
> 
> "????????" was shown because `DW_CFA_restore` is not supported in `DwarfParser`.
> This PR implements `DW_CFA_restore`, and also implements `DW_CFA_restore_state` and `DW_CFA_restore` correctly using `stack`.

src/jdk.hotspot.agent/linux/native/libsaproc/dwarf.cpp line 206:

> 204:       case 0x0a: // DW_CFA_remember_state
> 205:         remember_state.push(_state);
> 206:         init_state(_state);

Is doing an `init_state()` correct here? It's not clear from the spec that DW_CFA_remember_state invalidates the current state.

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PR Review Comment: https://git.openjdk.org/jdk/pull/29779#discussion_r2823701490