On Thu, 30 Oct 2025 13:32:46 GMT, Yasumasa Suenaga <[email protected]> wrote:

>> `jhsdb jstack --mixed` with coredump cannot resolve function symbol which 
>> has `.cold` attribute.
>> 
>> 
>> ----------------- 120485 -----------------
>> "Thread-0" #24 prio=5 tid=0x00007f50dc1aa7c0 nid=120485 waiting on condition 
>> [0x00007f50c0d1a000]
>>    java.lang.Thread.State: TIMED_WAITING (sleeping)
>>    JavaThread state: _thread_blocked
>> 0x00007f50e4710735 __GI_abort + 0x8b
>> 0x00007f50e1e01f33 ????????
>> 
>> 
>> 0x7f50e1e01f33 was `os::abort(bool, void const*, void const*) [clone .cold]` 
>> and I could see it in GDB. However it has `.cold` suffix, it means the code 
>> has been relocated as ["cold" 
>> function](https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-cold-function-attribute).
>>  In GDB, we can see the code in another area from function body as following:
>> 
>> 
>> (gdb) disas 0x7f50e1e01f2e, 0x7f50e1e01f34
>> Dump of assembler code from 0x7f50e1e01f2e to 0x7f50e1e01f34:
>>    0x00007f50e1e01f2e <_ZN2os5abortEbPKvS1_.cold+0>: call 0x7f50e1e01010 
>> <abort@plt>
>> => 0x00007f50e1e01f33: nop
>> End of assembler dump.
>> 
>> 
>> libsaproc.so checks address range to resolve symbol whether the address is 
>> in between `start` and `start + size - 1`. As you can see in assembler dump, 
>> the code in `.cold` section is `call` instruction, thus IP points next 
>> `nop`, thus we should allow address range between `start` and `start + size`.
>> 
>> After this PR, you can see the right symbol as following:
>> 
>> 
>> ----------------- 120485 -----------------
>> "Thread-0" #24 prio=5 tid=0x00007f50dc1aa7c0 nid=120485 waiting on condition 
>> [0x00007f50c0d1a000]
>>    java.lang.Thread.State: TIMED_WAITING (sleeping)
>>    JavaThread state: _thread_blocked
>> 0x00007f50e4710735      __GI_abort + 0x8b
>> 0x00007f50e1e01f33      os::abort(bool, void const*, void const*) [clone 
>> .cold] + 0x5
>
> Yasumasa Suenaga has updated the pull request incrementally with one 
> additional commit since the last revision:
> 
>   Clarify comment about RIP-1 fallback handling

Thanks, yes we should go ahead.
Is it OK to update the JBS issue and this PR title, maybe to:
Mixed mode jhsdb jstack cannot resolve symbol in function ending in call

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

PR Comment: https://git.openjdk.org/jdk/pull/27846#issuecomment-3472017765

Reply via email to