/proc/cpuinfo on Linux 3.5 (and Linux 3.5.1) contains different values for cpu0's "siblings" and cpu1's "siblings" and "cpu cores", compared to the values seen on Linux 3.4.8 (and previous versions).
I came across a relevant-looking fix  but it's already included in Linux 3.5.x.
The CPU is an Intel Atom N270  (1 core with Hyper-Threading).
Created attachment 77751 [details]
Diff of /proc/cpuinfo between Linux 3.4.8 and Linux 3.5.1
I'm experiencing the same bug with linux 3.5.3
Originally reported in the Arch bugtracker: