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Message-ID: <20260203112040.01bbb8e9@gandalf.local.home>
Date: Tue, 3 Feb 2026 11:20:40 -0500
From: Steven Rostedt <rostedt@...dmis.org>
To: "jempty.liang" <imntjempty@....com>
Cc: mhiramat@...nel.org, mark.rutland@....com,
mathieu.desnoyers@...icios.com, linux-kernel@...r.kernel.org,
linux-trace-kernel@...r.kernel.org
Subject: Re: [PATCH v2] tracing: Fix funcgraph_exit calltime/rettime offset
for 32-bit ARM
On Tue, 3 Feb 2026 09:30:18 -0500
Steven Rostedt <rostedt@...dmis.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
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)
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