Re: [PATCH v2] driver core: Fix userspace expectations of uevent_show() as a probe barrier

[Greg KH <gregkh@linuxfoundation.org>]

On Mon, Oct 28, 2024 at 03:57:55PM -0700, Dan Williams wrote:
> Thorsten Leemhuis wrote:
> > On 08.10.24 02:26, Dan Williams wrote:
> > > Dan Williams wrote:
> > >> Changes since v1 [1]:
> > >> - Move the new "locked" infrastructure to private header files to make
> > >>   it clear it is not approved for general usage (Greg)
> > > 
> > > Greg, per the 0day report and further testing I am missing something
> > > subtle in using kernfs open files to pin device objects. So hold off on
> > > this for now until I can get that root caused. If someone else can spot
> > > what I missed feel free to chime in, but otherwise I will circle back.
> > > 
> > > If I don't get back to this before -rc6 I think the theoretical deadlock
> > > that would be re-introduced by a revert of 15fffc6a5624 would be
> > > preferable to this reported regression. I am not aware of any reports of
> > > that deadlock triggering in practice.
> > Was there any progress? If not: given that Linus prefers to have things
> > fixed by -rc6 I wonder if now would be a good time to get the revert on
> > track for a merge later this week.
> 
> Revert 15fffc6a5624 ("driver core: Fix uevent_show() vs driver detach
> race"), which reintroduces a theoretical lockdep splat, is my preference
> at this point.
> 
> Even if I had a new version of this replacement patch in hand today I
> would still want it to be v6.13 material, not v6.12-rc. It deserves a
> full kernel cycle soak time to shake out issues before release.

Ok, I'll do the revert in my tree and push it for the next -rc release
thanks.

greg k-h