Re: [PATCH 02/16] x86, mce: call-in should be after updating global_nwo

huang ying
2009-06-15T08:26:19Z

2009/6/15 Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>:
> At the beginning of Monarch synchronization, processors wait until
> all of them have entered the exception handler and then check the
> global_nwo to determine if any of them saw a fatal event.
>
> However since current code does call-in before updating global_nwo,
> it might happen that the global_nwo does not reflect some of local
> nwo at the time.  This might break printing corrected errors not
> handled yet on panic.

This is almost same as the patch that I just posted. I think this is
because it trigger a failure in mce-test suite, and we both find the
failure.

But your patch lacks memory barrier between mce_callin and global_nwo
updating/reading. Atomic operations does not imply memory barrier.

Best Regards,
Huang Ying