Re: [PATCH v2 03/10] blktrace: fix debugfs use after free

[Luis Chamberlain]

On Wed, Apr 22, 2020 at 12:29:42AM -0700, Christoph Hellwig wrote:
> On Mon, Apr 20, 2020 at 08:41:56PM +0000, Luis Chamberlain wrote:
> > Its already there. And yes, after my changes it is technically possible
> > to just re-use it directly. But this is complicated by a few things. One
> > is that at this point in time, asynchronous request_queue removal is
> > still possible, and so a race was exposed where a requeust_queue may be
> > lingering but its old device is gone. That race is fixed by reverting us
> > back to synchronous request_queue removal, therefore ensuring that the
> > debugfs dir exists so long as the device does.
> > 
> > I can remove the debugfs_lookup() *after* we revert to synchronous
> > request_queue removal, or we just re-order the patches so that the
> > revert happens first. That should simplify this patch.
> 
> Yes, please move the synchronous removal first instead of working around
> the current problems.

Sounds good. At first it was questionable, now its understood we need it.

  Luis