Re: [linus:master] [eventfs] 852e46e239: BUG:unable_to_handle_page_fault_for_address

From: Steven Rostedt <rostedt@goodmis.org>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: kernel test robot <oliver.sang@intel.com>,
	oe-lkp@lists.linux.dev, lkp@intel.com,
	linux-kernel@vger.kernel.org,
	Masami Hiramatsu <mhiramat@kernel.org>,
	Mark Rutland <mark.rutland@arm.com>,
	Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
	Christian Brauner <brauner@kernel.org>,
	Al Viro <viro@zeniv.linux.org.uk>,
	Ajay Kaher <ajay.kaher@broadcom.com>,
	linux-trace-kernel@vger.kernel.org
Subject: Re: [linus:master] [eventfs] 852e46e239: BUG:unable_to_handle_page_fault_for_address
Date: Wed, 31 Jan 2024 14:42:16 -0500	[thread overview]
Message-ID: <20240131144217.0130b517@gandalf.local.home> (raw)
In-Reply-To: <CAHk-=wgh0otaSyV0MNrQpwFDTjT3=TWV94Wit2eUuPdh2KdyVg@mail.gmail.com>

On Wed, 31 Jan 2024 11:35:18 -0800
Linus Torvalds <torvalds@linux-foundation.org> wrote:

> On Wed, 31 Jan 2024 at 07:58, Steven Rostedt <rostedt@goodmis.org> wrote:
> >
> > BTW, I ran my full test suite on your patches with the below updates and it
> > all passed.  
> 
> Those patch updates all look sane to me.
> 
> > I can break up and clean up the patches so that they are bisectable, and if
> > that passes the bisectable portion of my tests, I can still send them to
> > you for 6.8.  
> 
> Ack. That series you posted looks fine. I didn't do any actual testing
> or applying the patches, just looking at them.
> 
> The one thing I noticed is that the 'llist' removal still needs to be
> done. The logical point is that "[PATCH v2 7/7]" where the
> eventfs_workfn stuff is ripped out.
> 
> And the 'rcu' head should now be a union with something that is no
> longer used after the last kref. The only thing that *is* used after
> the last kref is the "is_freed" bit, so there's lots of choice. Using
> the 'struct list_head listl' that is used for the child list would
> seem to be the obvious choice, but it could be anything (including all
> of the beginning of that eventfs_inode, but then you would need to
> group that as another nested unnamed struct, so picking a "big enough"
> entry like 'list' makes it syntactically simpler.

Yeah, that was what I was talking about in my cover letter with:

  Note, there's more clean ups that can happen. One being cleaning up the
  eventfs_inode structure. But that's not critical now and can be added
  later.

I just want to get the majority of the broken parts done. The clean up of
the eventfs_inode is something that I'd add a separate patch. Not sure that
falls in your "fixes" category for 6.8.

-- Steve