Re: [PATCH 1/2] tracefs: Remove unnecessary debug_fs checks.

[Steven Rostedt]

On Mon, 22 Jun 2020 10:30:18 +0200
Peter Enderborg <peter.enderborg@xxxxxxxx> 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@xxxxxxxxx>
> Signed-off-by: Peter Enderborg <peter.enderborg@xxxxxxxx>

Acked-by: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx>

-- 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);
>  
>  	/*