I was having a similar problem on my old laptop. It seemed a lot more
sensitive to the problem on later kernels.
What was actually happening is that the last time the laptop went in for
repairs they did not seat the heat sink correctly. It slowly worked
itself loose. After regreasing it with heat sink grease (not a heat sink
pad, but actual silver grease) and reseating it and tightening it down,
the machine worked fine. (I also found some nasty tool marks in the soft
metal next to the heat sink that shows that whoever did it slipped at
least once.)
Sometimes hardware problems increase slowly.
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