Re: [PATCH v2] tracing: Fix funcgraph_exit calltime/rettime offset for 32-bit ARM

["jempty.liang" <imntjempty@163.com>]

At 2026-02-04 00:20:40, "Steven Rostedt" <rostedt@goodmis.org> wrote:
>On Tue, 3 Feb 2026 09:30:18 -0500
>Steven Rostedt <rostedt@goodmis.org> wrote:
>
>> > On the 32-bit ARM platform, when _type is unsigned long long, the resulting align value is 8 instead of the expected 4.  
>> > >     
>> 
>> Are you saying this still doesn't work?
>> 
>> That would be an issue because then it would have the same bugs with
>> generic trace events which uses the same solution.
>
>OK, so talking with others that know more about arm32 than I do, it can
>indeed still produce an 8 byte alignment.
>
>Anyway, I still want to fix it properly. Does this patch work for you?
>
>-- Steve

Yes, I've verified it and this patch works correctly on the 32-bit ARM platform.

>
>diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
>index b6d42fe06115..c11edec5d8f5 100644
>--- a/kernel/trace/trace.h
>+++ b/kernel/trace/trace.h
>@@ -68,14 +68,17 @@ enum trace_type {
> #undef __field_fn
> #define __field_fn(type, item)		type	item;
> 
>+#undef __field_packed
>+#define __field_packed(type, item)	type	item;
>+
> #undef __field_struct
> #define __field_struct(type, item)	__field(type, item)
> 
> #undef __field_desc
> #define __field_desc(type, container, item)
> 
>-#undef __field_packed
>-#define __field_packed(type, container, item)
>+#undef __field_desc_packed
>+#define __field_desc_packed(type, container, item)
> 
> #undef __array
> #define __array(type, item, size)	type	item[size];
>diff --git a/kernel/trace/trace_entries.h b/kernel/trace/trace_entries.h
>index f6a8d29c0d76..54417468fdeb 100644
>--- a/kernel/trace/trace_entries.h
>+++ b/kernel/trace/trace_entries.h
>@@ -79,8 +79,8 @@ 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_desc_packed(unsigned long,	graph_ent,	func	)
>+		__field_desc_packed(unsigned long,	graph_ent,	depth	)
> 		__dynamic_array(unsigned long,	args				)
> 	),
> 
>@@ -96,9 +96,9 @@ FTRACE_ENTRY_PACKED(fgraph_retaddr_entry, fgraph_retaddr_ent_entry,
> 
> 	F_STRUCT(
> 		__field_struct(	struct fgraph_retaddr_ent,	graph_rent	)
>-		__field_packed(	unsigned long,	graph_rent.ent,	func		)
>-		__field_packed(	unsigned long,	graph_rent.ent,	depth		)
>-		__field_packed(	unsigned long,	graph_rent,	retaddr		)
>+		__field_desc_packed(	unsigned long,	graph_rent.ent,	func	)
>+		__field_desc_packed(	unsigned long,	graph_rent.ent,	depth	)
>+		__field_desc_packed(	unsigned long,	graph_rent,	retaddr	)
> 		__dynamic_array(unsigned long,	args				)
> 	),
> 
>@@ -123,12 +123,12 @@ FTRACE_ENTRY_PACKED(funcgraph_exit, ftrace_graph_ret_entry,
> 
> 	F_STRUCT(
> 		__field_struct(	struct ftrace_graph_ret,	ret	)
>-		__field_packed(	unsigned long,	ret,		func	)
>-		__field_packed(	unsigned long,	ret,		retval	)
>-		__field_packed(	unsigned int,	ret,		depth	)
>-		__field_packed(	unsigned int,	ret,		overrun	)
>-		__field(unsigned long long,	calltime		)
>-		__field(unsigned long long,	rettime			)
>+		__field_desc_packed(	unsigned long,	ret,	func	)
>+		__field_desc_packed(	unsigned long,	ret,	retval	)
>+		__field_desc_packed(	unsigned int,	ret,	depth	)
>+		__field_desc_packed(	unsigned int,	ret,	overrun	)
>+		__field_packed(unsigned long long,	calltime)
>+		__field_packed(unsigned long long,	rettime	)
> 	),
> 
> 	F_printk("<-- %ps (%u) (start: %llx  end: %llx) over: %u retval: %lx",
>@@ -146,11 +146,11 @@ FTRACE_ENTRY_PACKED(funcgraph_exit, ftrace_graph_ret_entry,
> 
> 	F_STRUCT(
> 		__field_struct(	struct ftrace_graph_ret,	ret	)
>-		__field_packed(	unsigned long,	ret,		func	)
>-		__field_packed(	unsigned int,	ret,		depth	)
>-		__field_packed(	unsigned int,	ret,		overrun	)
>-		__field(unsigned long long,	calltime		)
>-		__field(unsigned long long,	rettime			)
>+		__field_desc_packed(	unsigned long,	ret,	func	)
>+		__field_desc_packed(	unsigned int,	ret,	depth	)
>+		__field_desc_packed(	unsigned int,	ret,	overrun	)
>+		__field_packed(unsigned long long,	calltime	)
>+		__field_packed(unsigned long long,	rettime		)
> 	),
> 
> 	F_printk("<-- %ps (%u) (start: %llx  end: %llx) over: %u",
>diff --git a/kernel/trace/trace_export.c b/kernel/trace/trace_export.c
>index 1698fc22afa0..32a42ef31855 100644
>--- a/kernel/trace/trace_export.c
>+++ b/kernel/trace/trace_export.c
>@@ -42,11 +42,14 @@ static int ftrace_event_register(struct trace_event_call *call,
> #undef __field_fn
> #define __field_fn(type, item)				type item;
> 
>+#undef __field_packed
>+#define __field_packed(type, item)			type item;
>+
> #undef __field_desc
> #define __field_desc(type, container, item)		type item;
> 
>-#undef __field_packed
>-#define __field_packed(type, container, item)		type item;
>+#undef __field_desc_packed
>+#define __field_desc_packed(type, container, item)	type item;
> 
> #undef __array
> #define __array(type, item, size)			type item[size];
>@@ -104,11 +107,14 @@ static void __always_unused ____ftrace_check_##name(void)		\
> #undef __field_fn
> #define __field_fn(_type, _item) __field_ext(_type, _item, FILTER_TRACE_FN)
> 
>+#undef __field_packed
>+#define __field_packed(_type, _item) __field_ext_packed(_type, _item, FILTER_OTHER)
>+
> #undef __field_desc
> #define __field_desc(_type, _container, _item) __field_ext(_type, _item, FILTER_OTHER)
> 
>-#undef __field_packed
>-#define __field_packed(_type, _container, _item) __field_ext_packed(_type, _item, FILTER_OTHER)
>+#undef __field_desc_packed
>+#define __field_desc_packed(_type, _container, _item) __field_ext_packed(_type, _item, FILTER_OTHER)
> 
> #undef __array
> #define __array(_type, _item, _len) {					\
>@@ -146,11 +152,14 @@ static struct trace_event_fields ftrace_event_fields_##name[] = {	\
> #undef __field_fn
> #define __field_fn(type, item)
> 
>+#undef __field_packed
>+#define __field_packed(type, item)
>+
> #undef __field_desc
> #define __field_desc(type, container, item)
> 
>-#undef __field_packed
>-#define __field_packed(type, container, item)
>+#undef __field_desc_packed
>+#define __field_desc_packed(type, container, item)
> 
> #undef __array
> #define __array(type, item, len)