[PATCH] tracing/synthetic: Print out u64 values properly

[PATCH] tracing/synthetic: Print out u64 values properly

[Tero Kristo]

The synth traces incorrectly print pointer to the synthetic event values
instead of the actual value when using u64 type. Fix by addressing the
contents of the union properly.

Fixes: ddeea494a16f ("tracing/synthetic: Use union instead of casts")
Cc: stable@vger.kernel.org
Signed-off-by: Tero Kristo <tero.kristo@linux.intel.com>
---
 kernel/trace/trace_events_synth.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/trace/trace_events_synth.c b/kernel/trace/trace_events_synth.c
index 7fff8235075f..070365959c0a 100644
--- a/kernel/trace/trace_events_synth.c
+++ b/kernel/trace/trace_events_synth.c
@@ -337,7 +337,7 @@ static void print_synth_event_num_val(struct trace_seq *s,
 		break;
 
 	default:
-		trace_seq_printf(s, print_fmt, name, val, space);
+		trace_seq_printf(s, print_fmt, name, val->as_u64, space);
 		break;
 	}
 }
-- 
2.40.1

Re: [PATCH] tracing/synthetic: Print out u64 values properly

[Masami Hiramatsu]

Hi Tero,

On Mon, 11 Sep 2023 17:17:04 +0300
Tero Kristo <tero.kristo@linux.intel.com> wrote:

> The synth traces incorrectly print pointer to the synthetic event values
> instead of the actual value when using u64 type. Fix by addressing the
> contents of the union properly.

Thanks for pointing it out.
But I would like to see a new "case 8:" print code instead of changing
"default". Can you keep the default as it is and add "case 8:" case there?

Thanks,

> 
> Fixes: ddeea494a16f ("tracing/synthetic: Use union instead of casts")
> Cc: stable@vger.kernel.org
> Signed-off-by: Tero Kristo <tero.kristo@linux.intel.com>
> ---
>  kernel/trace/trace_events_synth.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/kernel/trace/trace_events_synth.c b/kernel/trace/trace_events_synth.c
> index 7fff8235075f..070365959c0a 100644
> --- a/kernel/trace/trace_events_synth.c
> +++ b/kernel/trace/trace_events_synth.c
> @@ -337,7 +337,7 @@ static void print_synth_event_num_val(struct trace_seq *s,
>  		break;
>  
>  	default:
> -		trace_seq_printf(s, print_fmt, name, val, space);
> +		trace_seq_printf(s, print_fmt, name, val->as_u64, space);
>  		break;
>  	}
>  }
> -- 
> 2.40.1
> 


-- 
Masami Hiramatsu (Google) <mhiramat@kernel.org>

Re: [PATCH] tracing/synthetic: Print out u64 values properly

[Tero Kristo]

Hi Masami,

On 15/09/2023 09:01, Masami Hiramatsu (Google) wrote:
> Hi Tero,
>
> On Mon, 11 Sep 2023 17:17:04 +0300
> Tero Kristo <tero.kristo@linux.intel.com> wrote:
>
>> The synth traces incorrectly print pointer to the synthetic event values
>> instead of the actual value when using u64 type. Fix by addressing the
>> contents of the union properly.
> Thanks for pointing it out.
> But I would like to see a new "case 8:" print code instead of changing
> "default". Can you keep the default as it is and add "case 8:" case there?

Are you sure about that? I think keeping the default as is would just 
print out a useless pointer value to the synth event itself (which is 
what happened with u64 type.)

Anyways, that requires a new patch to be created on top as this has hit 
the mainline as a fix already.

-Tero


>
> Thanks,
>
>> Fixes: ddeea494a16f ("tracing/synthetic: Use union instead of casts")
>> Cc: stable@vger.kernel.org
>> Signed-off-by: Tero Kristo <tero.kristo@linux.intel.com>
>> ---
>>   kernel/trace/trace_events_synth.c | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/kernel/trace/trace_events_synth.c b/kernel/trace/trace_events_synth.c
>> index 7fff8235075f..070365959c0a 100644
>> --- a/kernel/trace/trace_events_synth.c
>> +++ b/kernel/trace/trace_events_synth.c
>> @@ -337,7 +337,7 @@ static void print_synth_event_num_val(struct trace_seq *s,
>>   		break;
>>   
>>   	default:
>> -		trace_seq_printf(s, print_fmt, name, val, space);
>> +		trace_seq_printf(s, print_fmt, name, val->as_u64, space);
>>   		break;
>>   	}
>>   }
>> -- 
>> 2.40.1
>>
>

Re: [PATCH] tracing/synthetic: Print out u64 values properly

[Masami Hiramatsu]

Hi Tero,

On Fri, 15 Sep 2023 13:46:45 +0300
Tero Kristo <tero.kristo@linux.intel.com> wrote:

> Hi Masami,
> 
> On 15/09/2023 09:01, Masami Hiramatsu (Google) wrote:
> > Hi Tero,
> >
> > On Mon, 11 Sep 2023 17:17:04 +0300
> > Tero Kristo <tero.kristo@linux.intel.com> wrote:
> >
> >> The synth traces incorrectly print pointer to the synthetic event values
> >> instead of the actual value when using u64 type. Fix by addressing the
> >> contents of the union properly.
> > Thanks for pointing it out.
> > But I would like to see a new "case 8:" print code instead of changing
> > "default". Can you keep the default as it is and add "case 8:" case there?
> 
> Are you sure about that? I think keeping the default as is would just 
> print out a useless pointer value to the synth event itself (which is 
> what happened with u64 type.)

Yeah, I think the "default" here means no correct way to show the value
in it. So anyway, if we know the size is 8 and there is val->as_u64,
there should be "case 8:".

> 
> Anyways, that requires a new patch to be created on top as this has hit 
> the mainline as a fix already.

Oops, I missed that.

Thank you!

> 
> -Tero
> 
> 
> >
> > Thanks,
> >
> >> Fixes: ddeea494a16f ("tracing/synthetic: Use union instead of casts")
> >> Cc: stable@vger.kernel.org
> >> Signed-off-by: Tero Kristo <tero.kristo@linux.intel.com>
> >> ---
> >>   kernel/trace/trace_events_synth.c | 2 +-
> >>   1 file changed, 1 insertion(+), 1 deletion(-)
> >>
> >> diff --git a/kernel/trace/trace_events_synth.c b/kernel/trace/trace_events_synth.c
> >> index 7fff8235075f..070365959c0a 100644
> >> --- a/kernel/trace/trace_events_synth.c
> >> +++ b/kernel/trace/trace_events_synth.c
> >> @@ -337,7 +337,7 @@ static void print_synth_event_num_val(struct trace_seq *s,
> >>   		break;
> >>   
> >>   	default:
> >> -		trace_seq_printf(s, print_fmt, name, val, space);
> >> +		trace_seq_printf(s, print_fmt, name, val->as_u64, space);
> >>   		break;
> >>   	}
> >>   }
> >> -- 
> >> 2.40.1
> >>
> >


-- 
Masami Hiramatsu (Google) <mhiramat@kernel.org>

Re: [PATCH] tracing/synthetic: Print out u64 values properly

[Steven Rostedt]

On Fri, 15 Sep 2023 23:16:13 +0900
Masami Hiramatsu (Google) <mhiramat@kernel.org> wrote:

> > Anyways, that requires a new patch to be created on top as this has hit 
> > the mainline as a fix already.  
> 
> Oops, I missed that.

Yeah, I took that because it matched the original case, which was it being u64.

-- Steve