Re: [PATCH tracing/kprobes 3/3] tracing/ftrace: Fix to checkcreate_event_dir() when adding new events

[Frederic Weisbecker]

On Fri, Sep 25, 2009 at 11:20:54AM -0700, Masami Hiramatsu wrote:
> Check result of create_event_dir() and add ftrace_event_call to
> ftrace_events list only if it is succeeded. Thanks Li for pointing it out.
> 
> Signed-off-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
> Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
> Cc: Jim Keniston <jkenisto@xxxxxxxxxx>
> Cc: Ananth N Mavinakayanahalli <ananth@xxxxxxxxxx>
> Cc: Andi Kleen <ak@xxxxxxxxxxxxxxx>
> Cc: Christoph Hellwig <hch@xxxxxxxxxxxxx>
> Cc: Frank Ch. Eigler <fche@xxxxxxxxxx>
> Cc: Frederic Weisbecker <fweisbec@xxxxxxxxx>
> Cc: H. Peter Anvin <hpa@xxxxxxxxx>
> Cc: Ingo Molnar <mingo@xxxxxxx>
> Cc: Jason Baron <jbaron@xxxxxxxxxx>
> Cc: K.Prasad <prasad@xxxxxxxxxxxxxxxxxx>
> Cc: Lai Jiangshan <laijs@xxxxxxxxxxxxxx>
> Cc: Li Zefan <lizf@xxxxxxxxxxxxxx>
> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
> Cc: Srikar Dronamraju <srikar@xxxxxxxxxxxxxxxxxx>
> Cc: Tom Zanussi <tzanussi@xxxxxxxxx>
> ---
> 
>  kernel/trace/trace_events.c |   29 +++++++++++++++++++++--------
>  1 files changed, 21 insertions(+), 8 deletions(-)
> 
> diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
> index a4b7c9a..f03cda3 100644
> --- a/kernel/trace/trace_events.c
> +++ b/kernel/trace/trace_events.c
> @@ -957,12 +957,14 @@ static int __trace_add_event_call(struct ftrace_event_call *call)
>  	if (!d_events)
>  		return -ENOENT;
>  
> -	list_add(&call->list, &ftrace_events);
>  	ret = event_create_dir(call, d_events, &ftrace_event_id_fops,
>  				&ftrace_enable_fops, &ftrace_event_filter_fops,
>  				&ftrace_event_format_fops);
>  	if (ret < 0)
> -		list_del(&call->list);
> +		pr_warning("Could not create directory of trace events/%s\n",
> +			   call->name);




We already have such warnings in event_create_dir, with even more granularity
against the failure reason. The patch is fine, but I'll just remove the warning
introduced inside while applying it.

Thanks.


PS: Also I guess we could add the event in the list right from
event_create_dir()...

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