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: Mon, 29 Jan 2024 18:15:28 -0500	[thread overview]
Message-ID: <20240129181528.2aa5e39f@gandalf.local.home> (raw)
In-Reply-To: <20240129174732.1cea0d69@gandalf.local.home>

On Mon, 29 Jan 2024 17:47:32 -0500
Steven Rostedt <rostedt@goodmis.org> wrote:

> > And I hope there aren't any other stupid things I missed like that.  
> 
> Well the preliminary tests pass with this added to your patch:

Spoke too soon. The later tests started failing.

It fails on creating a kprobe, deleting it, and then recreating it. Even
though the directory is there, it can't be accessed.

 # cd /sys/kernel/tracing

// Create a kprobe

 # echo 'p:sched schedule' >> kprobe_events 
 # ls events/kprobes/
enable  filter  sched

// Now delete the kprobe

 # echo '-:sched schedule' >> kprobe_events

// Make sure it's gone

 # ls events/kprobes/
ls: cannot access 'events/kprobes/': No such file or directory

// Recreate it

 # echo 'p:sched schedule' >> kprobe_events 
 # ls events/kprobes/
ls: cannot access 'events/kprobes/': No such file or directory
 # ls events | grep kprobes
kprobes

No longer able to access it.

 # ls -l events | grep kprobes
ls: cannot access 'events/kprobes': No such file or directory
d????????? ? ?    ?    ?            ? kprobes

-- Steve