RFR: 8377947: Test serviceability/sa/TestJhsdbJstackMixedCore.java failed on linux-x64 [v2]

[Kevin Walls]

On Thu, 19 Feb 2026 00:21:03 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`.
>
> Yasumasa Suenaga has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Should not initialize state in DW_CFA_remember_state

Looks good, looks like a faithful move of the individual dwarf state variables into something that can be kept on a stack.

src/jdk.hotspot.agent/linux/native/libsaproc/dwarf.cpp line 209:

> 207:       case 0x0b: // DW_CFA_restore_state
> 208:         if (remember_state.empty()) {
> 209:           print_debug("DWARF: Remember State is empty even though DW_CFA_restore_state is saw.\n");

nit:  "is seen" not "is saw" 8-)

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PR Comment: https://git.openjdk.org/jdk/pull/29779#issuecomment-3958027739
PR Review Comment: https://git.openjdk.org/jdk/pull/29779#discussion_r2851915094