Re: Regression with a0747a859ef6 ("bdi: add error handle for bdi_debug_register")

[Bruno Wolff III]

On Sun, Dec 17, 2017 at 21:43:50 +0800,
 weiping zhang <zwp10758@xxxxxxxxx> wrote:
> Hi, thanks for testing, I think you first reproduce this issue(got WARNING
> at device_add_disk) by your own build, then add my debug patch.

The problem is still in rc4. Reverting the commit still fixes the problem. 
I tested that warning level messages should appear using lkdtm. While 
there could be something weird relating to the WARN_ON macro, more likely 
there is something different about the boots with the kernels I build 
(the exact way initramfs is built is probably different) and probably 
that (WARN_ON) code is not getting executed.