On 13.11.19 22:24, Dave Hansen wrote:
On 11/13/19 12:23 AM, Paolo Bonzini wrote:
On 13/11/19 07:38, Jan Kiszka wrote:
When reading MCE, error code 0150h, ie. SRAR, I was wondering if that
couldn't simply be handled by the host. But I suppose the symptom of
that erratum is not "just" regular recoverable MCE, rather
sometimes/always an unrecoverable CPU state, despite the error code, right?
The erratum documentation talks explicitly about hanging the system, but
it's not clear if it's just a result of the OS mishandling the MCE, or
something worse. So I don't know. :( Pawan, do you?
It's "something worse".
I built a kernel module reproducer for this a long time ago. The
symptom I observed was the whole system hanging hard, requiring me to go
hit the power button. The MCE software machinery was not involved at
all from what I could tell.
Thanks for clarifying this - too bad.
About creating a unit test, I'd be personally happy to share my
reproducer, but I built it before this issue was root-caused. There are
actually quite a few underlying variants and a good unit test would make
sure to exercise all of them. My reproducer probably only exercised a
single case.
Would be interesting to see this. Ralf and tried something quickly, but
there seems to be a detail missing or wrong.
Jan
--
Siemens AG, Corporate Technology, CT RDA IOT SES-DE
Corporate Competence Center Embedded Linux
