tracing: Rename stacktrace field to common_stacktrace

The histogram and synthetic events can use a pseudo event called
"stacktrace" that will create a stacktrace at the time of the event and
use it just like it was a normal field. We have other pseudo events such
as "common_cpu" and "common_timestamp". To stay consistent with that,
convert "stacktrace" to "common_stacktrace". As this was used in older
kernels, to keep backward compatibility, this will act just like
"common_cpu" did with "cpu". That is, "cpu" will be the same as
"common_cpu" unless the event has a "cpu" field. In which case, the
event's field is used. The same is true with "stacktrace".

Also update the documentation to reflect this change.

Link: https://lore.kernel.org/linux-trace-kernel/20230523230913.6860e28d@rorschach.local.home

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Tom Zanussi <zanussi@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

1 files changed, 2 insertions, 0 deletions

diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 654ffa40457a..57e539d47989 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -194,6 +194,8 @@ static int trace_define_generic_fields(void)
 	__generic_field(int, common_cpu, FILTER_CPU);
 	__generic_field(char *, COMM, FILTER_COMM);
 	__generic_field(char *, comm, FILTER_COMM);
+	__generic_field(char *, stacktrace, FILTER_STACKTRACE);
+	__generic_field(char *, STACKTRACE, FILTER_STACKTRACE);
 
 	return ret;
 }