Re: [GIT PULL] tracing/kprobes: Fix field creation's bad error handling

[Masami Hiramatsu <mhiramat@redhat.com>]

Frederic Weisbecker wrote:
> Ingo,
> 
> Please pull the tracing/fixes branch that can be found at:
> 
> git://git.kernel.org/pub/scm/linux/kernel/git/frederic/random-tracing.git
> 	tracing/fixes
> 
> Thanks,
> 	Frederic
> ---
> 
> Frederic Weisbecker (1):
>       tracing/kprobes: Fix field creation's bad error handling
> 
> 
>  kernel/trace/trace_kprobe.c |    4 ++--
>  1 files changed, 2 insertions(+), 2 deletions(-)
> 
> ---
> From 12e22dfaaee46f70762beb1982a7b86a68317b11 Mon Sep 17 00:00:00 2001
> From: Frederic Weisbecker <fweisbec@gmail.com>
> Date: Tue, 8 Dec 2009 10:00:04 +0100
> Subject: [PATCH] tracing/kprobes: Fix field creation's bad error handling
> Cc: Lai Jiangshan <laijs@cn.fujitsu.com>, Steven Rostedt <rostedt@goodmis.org>, Masami Hiramatsu <mhiramat@redhat.com>, Li Zefan <lizf@cn.fujitsu.com>
> 
> When we define the common event fields in kprobe, we invert the error
> handling and return immediately in case of success. Then we omit
> to define specific kprobes fields (ip and nargs), and specific
> kretprobes fields (func, ret_ip, nargs). And we only define them
> when we fail to create common fields.
> 
> The most visible consequence is that we can't create filter for
> k(ret)probes specific fields.
> 
> This patch re-invert the success/error handling to fix it.
> 
> Reported-by: Lai Jiangshan <laijs@cn.fujitsu.com>
> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
> Cc: Steven Rostedt <rostedt@goodmis.org>
> Cc: Masami Hiramatsu <mhiramat@redhat.com>
> Cc: Li Zefan <lizf@cn.fujitsu.com>

Thanks for fix that.

Acked-by: Masami Hiramatsu <mhiramat@redhat.com>


Ingo, I think this should go to tip:urgent.

Thank you,

> ---
>  kernel/trace/trace_kprobe.c |    4 ++--
>  1 files changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
> index aff5f80..ca04523 100644
> --- a/kernel/trace/trace_kprobe.c
> +++ b/kernel/trace/trace_kprobe.c
> @@ -1114,7 +1114,7 @@ static int kprobe_event_define_fields(struct ftrace_event_call *event_call)
>  	struct trace_probe *tp = (struct trace_probe *)event_call->data;
>  
>  	ret = trace_define_common_fields(event_call);
> -	if (!ret)
> +	if (ret)
>  		return ret;
>  
>  	DEFINE_FIELD(unsigned long, ip, FIELD_STRING_IP, 0);
> @@ -1132,7 +1132,7 @@ static int kretprobe_event_define_fields(struct ftrace_event_call *event_call)
>  	struct trace_probe *tp = (struct trace_probe *)event_call->data;
>  
>  	ret = trace_define_common_fields(event_call);
> -	if (!ret)
> +	if (ret)
>  		return ret;
>  
>  	DEFINE_FIELD(unsigned long, func, FIELD_STRING_FUNC, 0);

-- 
Masami Hiramatsu

Software Engineer
Hitachi Computer Products (America), Inc.
Software Solutions Division

e-mail: mhiramat@redhat.com