RE: [PATCH] genhd: Do not hold event lock when scheduling workqueue elements

[Dexuan Cui]

> From: linux-block-owner@xxxxxxxxxxxxxxx [mailto:linux-block-
> owner@xxxxxxxxxxxxxxx] On Behalf Of Dexuan Cui
> with the linux-next kernel.
> 
> I can boot the guest with linux-next's next-20170130 without any issue,
> but since next-20170131 I haven't succeeded in booting the guest.
> 
> With next-20170203 (mentioned in my mail last Friday), I got the same
> calltrace as Hannes.
> 
> With today's linux-next (next-20170206), actually the calltrace changed to
> the below.
> [  122.023036]  ? remove_wait_queue+0x70/0x70
> [  122.051383]  async_synchronize_full+0x17/0x20
> [  122.076925]  do_init_module+0xc1/0x1f9
> [  122.097530]  load_module+0x24bc/0x2980
 
I don't know why it hangs here, but this is the same calltrace in my
last-Friday mail, which contains 2 calltraces. It looks the other calltrace has
been resolved by some changes between next-20170203 and today.

Here the kernel is trying to load the Hyper-V storage driver (hv_storvsc), and
the driver's __init and .probe have finished successfully and then the kernel
hangs here.

I believe something is broken recently, because I don't have any issue before
Jan 31. 

Thanks,
-- Dexuan