Re: [PATCH] tracing/ftrace: fix the check on nopped sites

Re: [PATCH] tracing/ftrace: fix the check on nopped sites

[Steven Rostedt]

On Mon, 16 Mar 2009, Frederic Weisbecker wrote:

> Impact: fix a dynamic tracing failure
> 
> Recently, the function and function graph tracers failed to use dynamic
> tracing after the following commit:
> 
> fa9d13cf135efbd454453a53b6299976bea245a9
> (ftrace: don't try to __ftrace_replace_code on !FTRACE_FL_CONVERTED rec)
> 
> The patch is right except a mistake on the check for the FTRACE_FL_CONVERTED
> flag. The code patching is aborted in case of successfully nopped sites.
> What we want is the opposite: ignore the callsites that haven't been nopped.
> 
> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
> ---
>  kernel/trace/ftrace.c |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)
> 
> diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
> index 90d5729..7847806 100644
> --- a/kernel/trace/ftrace.c
> +++ b/kernel/trace/ftrace.c
> @@ -537,7 +537,7 @@ static void ftrace_replace_code(int enable)
>  		 */
>  		if (rec->flags & FTRACE_FL_FREE ||
>  		    rec->flags & FTRACE_FL_FAILED ||
> -		    rec->flags & FTRACE_FL_CONVERTED)
> +		    !(rec->flags & FTRACE_FL_CONVERTED))
>  			continue;
>  
>  		/* ignore updates to this record's mcount site */
> -- 

Heh, I just found this bug too, and wrote a patch. But you posted before I 
did, so I'll let you have it ;-)

Acked-by: Steven Rostedt <srostedt@redhat.com>

-- Steve

Re: [PATCH] tracing/ftrace: fix the check on nopped sites

[Steven Rostedt]

Ingo,

I pulled this into my repo, and will post it shortly.

-- Steve

On Mon, 16 Mar 2009, Frederic Weisbecker wrote:

> Impact: fix a dynamic tracing failure
> 
> Recently, the function and function graph tracers failed to use dynamic
> tracing after the following commit:
> 
> fa9d13cf135efbd454453a53b6299976bea245a9
> (ftrace: don't try to __ftrace_replace_code on !FTRACE_FL_CONVERTED rec)
> 
> The patch is right except a mistake on the check for the FTRACE_FL_CONVERTED
> flag. The code patching is aborted in case of successfully nopped sites.
> What we want is the opposite: ignore the callsites that haven't been nopped.
> 
> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
> ---
>  kernel/trace/ftrace.c |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)
> 
> diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
> index 90d5729..7847806 100644
> --- a/kernel/trace/ftrace.c
> +++ b/kernel/trace/ftrace.c
> @@ -537,7 +537,7 @@ static void ftrace_replace_code(int enable)
>  		 */
>  		if (rec->flags & FTRACE_FL_FREE ||
>  		    rec->flags & FTRACE_FL_FAILED ||
> -		    rec->flags & FTRACE_FL_CONVERTED)
> +		    !(rec->flags & FTRACE_FL_CONVERTED))
>  			continue;
>  
>  		/* ignore updates to this record's mcount site */
> -- 
> 1.6.1
> 
> 

Re: [PATCH] tracing/ftrace: fix the check on nopped sites

[Zhaolei]

* From: "Steven Rostedt" <rostedt@goodmis.org>
> 
> 
> On Mon, 16 Mar 2009, Frederic Weisbecker wrote:
> 
>> Impact: fix a dynamic tracing failure
>> 
>> Recently, the function and function graph tracers failed to use dynamic
>> tracing after the following commit:
>> 
>> fa9d13cf135efbd454453a53b6299976bea245a9
>> (ftrace: don't try to __ftrace_replace_code on !FTRACE_FL_CONVERTED rec)
>> 
>> The patch is right except a mistake on the check for the FTRACE_FL_CONVERTED
>> flag. The code patching is aborted in case of successfully nopped sites.
>> What we want is the opposite: ignore the callsites that haven't been nopped.
>> 
>> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
>> ---
>>  kernel/trace/ftrace.c |    2 +-
>>  1 files changed, 1 insertions(+), 1 deletions(-)
>> 
>> diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
>> index 90d5729..7847806 100644
>> --- a/kernel/trace/ftrace.c
>> +++ b/kernel/trace/ftrace.c
>> @@ -537,7 +537,7 @@ static void ftrace_replace_code(int enable)
>>  */
>>  if (rec->flags & FTRACE_FL_FREE ||
>>      rec->flags & FTRACE_FL_FAILED ||
>> -     rec->flags & FTRACE_FL_CONVERTED)
>> +     !(rec->flags & FTRACE_FL_CONVERTED))
>>  continue;
>>  
>>  /* ignore updates to this record's mcount site */
>> -- 
Hello, 

Sorry for my fault.

B.R.
Zhaolei
> 
> Heh, I just found this bug too, and wrote a patch. But you posted before I 
> did, so I'll let you have it ;-)
> 
> Acked-by: Steven Rostedt <srostedt@redhat.com>
> 
> -- Steve
> 
> 
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