Hi all,

Building Linus' tree, today's linux-next build (powerpc
ppc6xx_defconfig gcc4.9) failed like this:

ERROR: modpost: "__divdi3" [drivers/block/nbd.ko] undefined!

Caused by commit

  fad7cd3310db ("nbd: add the check to prevent overflow in __nbd_ioctl()")

The added check_mul_overflow() call is being passed 64 bit values.
COMPILER_HAS_GENERIC_BUILTIN_OVERFLOW is not set for this build (see
include/linux/overflow.h).

-- 
Cheers,
Stephen Rothwell