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

[weiping zhang]

2017-12-15 19:10 GMT+08:00 Bruno Wolff III <bruno@xxxxxxxx>:
> On Fri, Dec 15, 2017 at 10:04:32 +0800,
>  weiping zhang <zwp10758@xxxxxxxxx> wrote:
>>
>> I just want to know WARN_ON WHAT in device_add_disk,
>> if bdi_register_owner return error code, it may fail at any step of
>> following:
>
>
> Was that output in the original boot log? I didn't see anything there that
> had the string WARN_ON. The first log was from a Fedora kernel. The second
Sorry to let you confuse, WARN_ON means we catch log as following:
WARNING: CPU: 3 PID: 3486 at block/genhd.c:680 device_add_disk+0x3d9/0x460

> from a kernel I built. I used a Fedora config though. The config was
> probably from one of their nodebug kernels, I could build another one using
> a config from a debug kernel. Would that likely provide what you are looking
> for?

Yes, please help reproduce this issue include my debug patch. Reproduce means
we can see WARN_ON in device_add_disk caused by failure of bdi_register_owner.