On Tue, Jul 06, 2021 at 03:29:11PM +0800, Ming Lei wrote:
> > and this seems to confirm, no I/O in flight.
> 
> What is the output of the following command after the hang is triggered?
> 
> (cd /sys/kernel/debug/block/nvme0n1 && find . -type f -exec grep -aH . {} \;)
> 
> Suppose the hang disk is nvme0n1.

see attachement

> No, percpu_ref_is_zero() is fine to be called in atomic mode.

Okay, that is what I hoped for :)