# Re: \[PATCH\] powerpc/stacktrace: fix raise\_backtrace\_ipi() logic

- From: Michael Ellerman \<mpe@ellerman.id.au\>
- Date: 2021-06-03 05:34:53 
- List: linuxppc-dev
- Page: https://ratatoskr.run/linuxppc-dev/2021/06/9522964
- Thread: https://ratatoskr.run/linuxppc-dev/2021/05/9522895/t.md

```text
Nathan Lynch [ref] writes:
> Hi Michael,
>
> Michael Ellerman [ref] writes:
>> Nathan Lynch [ref] writes:
>>> When smp_send_safe_nmi_ipi() indicates that the target CPU has
>>> responded to the IPI, skip the remote paca inspection
>>> fallback. Otherwise both the sending and target CPUs attempt the
>>> backtrace, usually creating a misleading ("didn't respond to backtrace
>>> IPI" is wrong) and interleaved mess:
>>
>> Thanks for fixing my bugs for me :)
>>
>
> Thanks for your review! I was beginning to think I had missed some
> subtletly here, thanks for illustrating it.
>
> I'll run with your proposed change below for the problem I'm working.

Thanks. I did test it a bit with the test_lockup module, but some real
world testing would be good too.

cheers
```