Re: [PATCH] blk-mq: fix up placement of debugfs directory of queue files

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

On Sat, Jul 06, 2019 at 10:07:14AM -0600, Jens Axboe wrote:
> On 7/6/19 9:50 AM, Greg Kroah-Hartman wrote:
> > When the blk-mq debugfs file creation logic was "cleaned up" it was
> > cleaned up too much, causing the queue file to not be created in the
> > correct location.  Turns out the check for the directory being present
> > is needed as if that has not happened yet, the files should not be
> > created, and the function will be called later on in the initialization
> > code so that the files can be created in the correct location.
> 
> How about we shove this in for 5.2 final? Trivial enough to do, and it
> would suck to have 5.2 released with this.

Sure, no objection from me!

> Though not sure what devices this actually impacts, I haven't noticed
> anything awry on my setups?

I can easily trigger this with loop devices.  I know Stephen reported
this and I don't know if that was the driver that caused it for him.  I
have also seen this happen in syzbot boot logs already, but again, don't
know what block devices they are using that causes this.

thanks,

greg k-h