Phantom nulls in usbdevs.h during 9-STABLE kernel build

[J David]

On Thu, Jul 4, 2013 at 11:27 PM, Konstantin Belousov <kostikbel at gmail.com>wrote:

> Try to apply r252528 and see if it helps.
>

OK, I svn up'd to get the clang changes and applied this patch as well.
 (Built tree off of local /usr/obj to avoid hitting the problem while
building with the patch.)

So far I have built the kernel 4 times with clang on NFS-mounted /usr/obj
with no problems, so things seem improved although reading the commit
description it sounds more like generalized corruption would result, so I
don't really understand why it would crop up so consistently only in this
one file.  (But it's entirely possible I misunderstood the commit message.)

It seems like usbdevs.h gets written once early in the boot process and
then never again.  So if this is indeed the fix, I wonder what the build
does to exercise that bug so frequently.

Thanks!