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Date:   Mon, 22 Jun 2020 09:47:04 -0400
From:   Steven Rostedt <rostedt@goodmis.org>
To:     Peter Enderborg <peter.enderborg@sony.com>
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        <linux-kernel@vger.kernel.org>,
        "Rafael J . Wysocki" <rafael@kernel.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Jonathan Corbet <corbet@lwn.net>, <linux-doc@vger.kernel.org>,
        Randy Dunlap <rdunlap@infradead.org>,
        Ingo Molnar <mingo@redhat.com>
Subject: Re: [PATCH 1/2] tracefs: Remove unnecessary debug_fs checks.
Message-ID: <20200622094704.589220a9@oasis.local.home>
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        <20200622083019.15479-1-peter.enderborg@sony.com>
        <20200622083019.15479-2-peter.enderborg@sony.com>
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On Mon, 22 Jun 2020 10:30:18 +0200
Peter Enderborg <peter.enderborg@sony.com> wrote:

> This is a preparation for debugfs restricted mode.
> We don't need debugfs to trace, the removed check stop tracefs to work
> if debugfs is not initialised. We instead tries to automount within
> debugfs and relay on it's handling. The code path is to create a
> backward compatibility from when tracefs was part of debugfs, it is now
> standalone and does not need debugfs. When debugfs is in restricted
> it is compiled in but not active and return EPERM to clients and
> tracefs wont work if it assumes it is active it is compiled in
> kernel.
> 
> Reported-by: kernel test robot <lkp@intel.com>
> Signed-off-by: Peter Enderborg <peter.enderborg@sony.com>

Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

-- Steve

> ---
>  kernel/trace/trace.c | 4 +---
>  1 file changed, 1 insertion(+), 3 deletions(-)
> 
> diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
> index ec44b0e2a19c..34ed82364edb 100644
> --- a/kernel/trace/trace.c
> +++ b/kernel/trace/trace.c
> @@ -8946,9 +8946,7 @@ struct dentry *tracing_init_dentry(void)
>  	if (tr->dir)
>  		return NULL;
>  
> -	if (WARN_ON(!tracefs_initialized()) ||
> -		(IS_ENABLED(CONFIG_DEBUG_FS) &&
> -		 WARN_ON(!debugfs_initialized())))
> +	if (WARN_ON(!tracefs_initialized()))
>  		return ERR_PTR(-ENODEV);
>  
>  	/*