Re: CPU hyperthreading turned on after soft power-cycle

From: Clarinet
Date: Wed Nov 16 2011 - 17:49:30 EST



Hi all,

Result of bisecting: v2.6.38-rc1 exhibits the problem. v2.6.37 and
many of the topic branches merged in the 2.6.38 merge window work ok.
Some other topic branches do not boot at all.

Jiri: if you have gitk installed, then "git bisect visualize" can help
get a sense of what's in the middle of the regression range.
"gitk --bisect --first-parent v2.6.37..v2.6.38-rc1" might be a good way
to find mainline commits to test before finding a topic branch to delve
into.

I have been able to narrow the interval manually a little bit from the
"top" (the bad side) and I will go on from the bottom now. However,
there seems to be a large area where kernels are unbootable for me -
they mostly stop when init is called and I do not know why.

Finally! After another 50+ compilations a have it! It took some time as first I had to find a reason why some revisions did not boot (almost 2/3 were unbootable and the first bad commit was among them). Having this solved I have been able to bisect without "skipping". The result is surprising (at least for me) - believe it or not, the first bad commit is 6610e089 "RTC: Rework RTC code to use timerqueue for events" from John Stultz (I am sending him a copy of this message).

I would never expect this would be a problem, but my understanding of this commit is very limited, so I am certainly missing the point. However, I have tried to compile 2.6.38 (which was "bad") with "Real Time Clock" configuration option turned off and it behaves "normally" then (= is "good").

Can you please comment this result? What does it mean? Any idea what is "wrong" there?

Best regards,

Jiri Polach

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