Re: Odd build breakage in 4.9-rc7

From: Linus Torvalds
Date: Wed Nov 30 2016 - 13:36:22 EST

On Wed, Nov 30, 2016 at 10:28 AM, Prarit Bhargava <prarit@xxxxxxxxxx> wrote:
> In my case I tracked this to commit 3637efb00864 ("x86/mce: Add PCI quirks to
> identify Xeons with machine check recovery") which adds the include for
> generated/autoksyms.h.

Ok, that at least makes some sense. The other blamed commit did not
seem to possibly make a difference.

> Searching LKML and I came across a report from Ken Moffat from a month ago:

Does a "make clean" get rid of it forever? Or does it come back?

If it's a one-time dependency issue that is because some header
dependency addition that the automatic dependency generator hadn't
caught, that might explain a bisection failure too: once the file
happens to get rebuilt (and the dependencies re-done), it starts
working even though the "happens to be rebuilt" had nothing to do with
the original bug.