[PATCH] ftrace: Fix type of ftrace_graph_ent_entry.depth

[PATCH] ftrace: Fix type of ftrace_graph_ent_entry.depth

[Ilya Leoshkevich]

ftrace_graph_ent.depth is int, but ftrace_graph_ent_entry.depth is
unsigned long. This confuses trace-cmd on big-endian systems and makes
it print a huge amount of spaces. Make the types match.

Fixes: ff5c9c576e75 ("ftrace: Add support for function argument to graph tracer")
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
---
 kernel/trace/trace_entries.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/trace/trace_entries.h b/kernel/trace/trace_entries.h
index ee40d4e6ad1c..ac6374b47fe3 100644
--- a/kernel/trace/trace_entries.h
+++ b/kernel/trace/trace_entries.h
@@ -80,11 +80,11 @@ FTRACE_ENTRY(funcgraph_entry, ftrace_graph_ent_entry,
 	F_STRUCT(
 		__field_struct(	struct ftrace_graph_ent,	graph_ent	)
 		__field_packed(	unsigned long,	graph_ent,	func		)
-		__field_packed(	unsigned long,	graph_ent,	depth		)
+		__field_packed(	int,		graph_ent,	depth		)
 		__dynamic_array(unsigned long,	args				)
 	),
 
-	F_printk("--> %ps (%lu)", (void *)__entry->func, __entry->depth)
+	F_printk("--> %ps (%d)", (void *)__entry->func, __entry->depth)
 );
 
 #ifdef CONFIG_FUNCTION_GRAPH_RETADDR
-- 
2.49.0

Re: [PATCH] ftrace: Fix type of ftrace_graph_ent_entry.depth

[Steven Rostedt]

On Fri, 11 Apr 2025 19:21:41 +0200
Ilya Leoshkevich <iii@linux.ibm.com> wrote:

>  
> -	F_printk("--> %ps (%lu)", (void *)__entry->func, __entry->depth)
> +	F_printk("--> %ps (%d)", (void *)__entry->func, __entry->depth)

depth should never be negative. Why did you use "%d" and not "%u" ?

-- Steve

Re: [PATCH] ftrace: Fix type of ftrace_graph_ent_entry.depth

[Ilya Leoshkevich]

On 2025-04-12 18:07, Steven Rostedt wrote:
> On Fri, 11 Apr 2025 19:21:41 +0200
> Ilya Leoshkevich <iii@linux.ibm.com> wrote:
> 
>> 
>> -	F_printk("--> %ps (%lu)", (void *)__entry->func, __entry->depth)
>> +	F_printk("--> %ps (%d)", (void *)__entry->func, __entry->depth)
> 
> depth should never be negative. Why did you use "%d" and not "%u" ?
> 
> -- Steve

I used int, because it's int in ftrace_graph_ent and all other events.
If you think it's a good idea, I can change them all to unsigned int in 
a follow-up patch.

Re: [PATCH] ftrace: Fix type of ftrace_graph_ent_entry.depth

[Steven Rostedt]

On Sat, 12 Apr 2025 23:01:05 +0200
Ilya Leoshkevich <iii@linux.ibm.com> wrote:

> On 2025-04-12 18:07, Steven Rostedt wrote:
> > On Fri, 11 Apr 2025 19:21:41 +0200
> > Ilya Leoshkevich <iii@linux.ibm.com> wrote:
> >   
> >> 
> >> -	F_printk("--> %ps (%lu)", (void *)__entry->func, __entry->depth)
> >> +	F_printk("--> %ps (%d)", (void *)__entry->func, __entry->depth)  
> > 
> > depth should never be negative. Why did you use "%d" and not "%u" ?
> > 
> > -- Steve  
> 
> I used int, because it's int in ftrace_graph_ent and all other events.
> If you think it's a good idea, I can change them all to unsigned int in 
> a follow-up patch.

Hmm, a change like that should have been in the change log and explained.

The reason the code has int is because it uses negative depth to break
out of iterations and such. But what is recorded is always zero or
positive.

Yeah, let's keep it exposed as unsigned int.

Thanks,

-- Stene