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

From: Linus Torvalds <torvalds@linux-foundation.org>
To: Steven Rostedt <rostedt@goodmis.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: Mon, 29 Jan 2024 16:01:25 -0800	[thread overview]
Message-ID: <CAHk-=wjbzw3=nwR5zGH9jqXgB8jj03wxWfdFDn=oAVCoymQQJg@mail.gmail.com> (raw)
In-Reply-To: <20240129174950.5a17a86c@gandalf.local.home>

On Mon, 29 Jan 2024 at 14:49, Steven Rostedt <rostedt@goodmis.org> wrote:
>
> Now I didn't change this last d_instantiate, because this is not called
> through the lookup code. This is the root events directory and acts more
> like debugfs. It's not "dynamically" added.

Ahh, yes, I see, the dentry was created (as a negative one) with
tracefs_start_creating() -> lookup_one_len().

So  yes, there d_instantiate() is correct, as it's exactly that "turn
negative dentry into a positive one" case.

I'll go see what's up with the "create it again" case - I don't
immediately see what's wrong.

              Linus