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Date: Wed, 31 Jan 2024 11:13:58 -0500
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
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On Wed, 31 Jan 2024 10:58:47 -0500
Steven Rostedt <rostedt@goodmis.org> wrote:

> @@ -788,6 +717,7 @@ static void init_once(void *foo)
>  {
>  	struct tracefs_inode *ti = (struct tracefs_inode *) foo;
>  
> +	memset(ti, 0, sizeof(*ti));
>  	inode_init_once(&ti->vfs_inode);
>  }
>  

Note, that inode_init_once() also does a memset on the entire inode, so the
initial memset is redundant on the inode portion. But I didn't think it was
really worth the time to complicate the code by optimizing it. I guess if I
changed the structure to:

 struct tracefs_inode {
+	struct inode            vfs_inode;
	unsigned long           flags;
	void                    *private;
-	struct inode            vfs_inode;
 };

I could have it do:

	memset_after(ti, 0, vfs_inode);

But this can be done as a separate clean up and doesn't need to be done now.

-- Steve