Merge tag 'trace-v6.2-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull tracing fix from Steven Rostedt:
 "Fix showing of TASK_COMM_LEN instead of its value

  The TASK_COMM_LEN was converted from a macro into an enum so that BTF
  would have access to it. But this unfortunately caused TASK_COMM_LEN
  to display in the format fields of trace events, as they are created
  by the TRACE_EVENT() macro and such, macros convert to their values,
  where as enums do not.

  To handle this, instead of using the field itself to be display, save
  the value of the array size as another field in the trace_event_fields
  structure, and use that instead.

  Not only does this fix the issue, but also converts the other trace
  events that have this same problem (but were not breaking tooling).

  With this change, the original work around b3bc8547d3be6 ("tracing:
  Have TRACE_DEFINE_ENUM affect trace event types as well") could be
  reverted (but that should be done in the merge window)"

* tag 'trace-v6.2-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  tracing: Fix TASK_COMM_LEN in trace event format file

5 files changed, 36 insertions, 11 deletions

diff --git a/include/linux/trace_events.h b/include/linux/trace_events.h
index 4342e996bcdb76..0e373222a6df8a 100644
--- a/include/linux/trace_events.h
+++ b/include/linux/trace_events.h
@@ -270,6 +270,7 @@ struct trace_event_fields {
 			const int  align;
 			const int  is_signed;
 			const int  filter_type;
+			const int  len;
 		};
 		int (*define_fields)(struct trace_event_call *);
 	};
diff --git a/include/trace/stages/stage4_event_fields.h b/include/trace/stages/stage4_event_fields.h
index affd541fd25eac..b6f679ae21aa77 100644
--- a/include/trace/stages/stage4_event_fields.h
+++ b/include/trace/stages/stage4_event_fields.h
@@ -26,7 +26,8 @@
 #define __array(_type, _item, _len) {					\
 	.type = #_type"["__stringify(_len)"]", .name = #_item,		\
 	.size = sizeof(_type[_len]), .align = ALIGN_STRUCTFIELD(_type),	\
-	.is_signed = is_signed_type(_type), .filter_type = FILTER_OTHER },
+	.is_signed = is_signed_type(_type), .filter_type = FILTER_OTHER,\
+	.len = _len },
 
 #undef __dynamic_array
 #define __dynamic_array(_type, _item, _len) {				\
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 4eb6d6b97a9fd9..085a31b978a56e 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -1282,6 +1282,7 @@ struct ftrace_event_field {
 	int			offset;
 	int			size;
 	int			is_signed;
+	int			len;
 };
 
 struct prog_entry;
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 33e0b4f8ebe626..6a46967192975b 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -114,7 +114,7 @@ trace_find_event_field(struct trace_event_call *call, char *name)
 
 static int __trace_define_field(struct list_head *head, const char *type,
 				const char *name, int offset, int size,
-				int is_signed, int filter_type)
+				int is_signed, int filter_type, int len)
 {
 	struct ftrace_event_field *field;
 
@@ -133,6 +133,7 @@ static int __trace_define_field(struct list_head *head, const char *type,
 	field->offset = offset;
 	field->size = size;
 	field->is_signed = is_signed;
+	field->len = len;
 
 	list_add(&field->link, head);
 
@@ -150,14 +151,28 @@ int trace_define_field(struct trace_event_call *call, const char *type,
 
 	head = trace_get_fields(call);
 	return __trace_define_field(head, type, name, offset, size,
-				    is_signed, filter_type);
+				    is_signed, filter_type, 0);
 }
 EXPORT_SYMBOL_GPL(trace_define_field);
 
+int trace_define_field_ext(struct trace_event_call *call, const char *type,
+		       const char *name, int offset, int size, int is_signed,
+		       int filter_type, int len)
+{
+	struct list_head *head;
+
+	if (WARN_ON(!call->class))
+		return 0;
+
+	head = trace_get_fields(call);
+	return __trace_define_field(head, type, name, offset, size,
+				    is_signed, filter_type, len);
+}
+
 #define __generic_field(type, item, filter_type)			\
 	ret = __trace_define_field(&ftrace_generic_fields, #type,	\
 				   #item, 0, 0, is_signed_type(type),	\
-				   filter_type);			\
+				   filter_type, 0);			\
 	if (ret)							\
 		return ret;
 
@@ -166,7 +181,7 @@ EXPORT_SYMBOL_GPL(trace_define_field);
 				   "common_" #item,			\
 				   offsetof(typeof(ent), item),		\
 				   sizeof(ent.item),			\
-				   is_signed_type(type), FILTER_OTHER);	\
+				   is_signed_type(type), FILTER_OTHER, 0);	\
 	if (ret)							\
 		return ret;
 
@@ -1588,12 +1603,17 @@ static int f_show(struct seq_file *m, void *v)
 		seq_printf(m, "\tfield:%s %s;\toffset:%u;\tsize:%u;\tsigned:%d;\n",
 			   field->type, field->name, field->offset,
 			   field->size, !!field->is_signed);
-	else
-		seq_printf(m, "\tfield:%.*s %s%s;\toffset:%u;\tsize:%u;\tsigned:%d;\n",
+	else if (field->len)
+		seq_printf(m, "\tfield:%.*s %s[%d];\toffset:%u;\tsize:%u;\tsigned:%d;\n",
 			   (int)(array_descriptor - field->type),
 			   field->type, field->name,
-			   array_descriptor, field->offset,
+			   field->len, field->offset,
 			   field->size, !!field->is_signed);
+	else
+		seq_printf(m, "\tfield:%.*s %s[];\toffset:%u;\tsize:%u;\tsigned:%d;\n",
+				(int)(array_descriptor - field->type),
+				field->type, field->name,
+				field->offset, field->size, !!field->is_signed);
 
 	return 0;
 }
@@ -2379,9 +2399,10 @@ event_define_fields(struct trace_event_call *call)
 			}
 
 			offset = ALIGN(offset, field->align);
-			ret = trace_define_field(call, field->type, field->name,
+			ret = trace_define_field_ext(call, field->type, field->name,
 						 offset, field->size,
-						 field->is_signed, field->filter_type);
+						 field->is_signed, field->filter_type,
+						 field->len);
 			if (WARN_ON_ONCE(ret)) {
 				pr_err("error code is %d\n", ret);
 				break;
diff --git a/kernel/trace/trace_export.c b/kernel/trace/trace_export.c
index d960f6b11b5e51..58f3946081e21a 100644
--- a/kernel/trace/trace_export.c
+++ b/kernel/trace/trace_export.c
@@ -111,7 +111,8 @@ static void __always_unused ____ftrace_check_##name(void)		\
 #define __array(_type, _item, _len) {					\
 	.type = #_type"["__stringify(_len)"]", .name = #_item,		\
 	.size = sizeof(_type[_len]), .align = __alignof__(_type),	\
-	is_signed_type(_type), .filter_type = FILTER_OTHER },
+	is_signed_type(_type), .filter_type = FILTER_OTHER,			\
+	.len = _len },
 
 #undef __array_desc
 #define __array_desc(_type, _container, _item, _len) __array(_type, _item, _len)