Commit 6107742d authored Oct 09, 2020 by Axel Rasmussen Committed by Steven Rostedt (VMware) Oct 15, 2020

tracing: support "bool" type in synthetic trace events

It's common [1] to define tracepoint fields as "bool" when they contain
a true / false value. Currently, defining a synthetic event with a
"bool" field yields EINVAL. It's possible to work around this by using
e.g. u8 (assuming sizeof(bool) is 1, and bool is unsigned; if either of
these properties don't match, you get EINVAL [2]).

Supporting "bool" explicitly makes hooking this up easier and more
portable for userspace.

[1]: grep -r "bool" include/trace/events/
[2]: check_synth_field() in kernel/trace/trace_events_hist.c

Link: https://lkml.kernel.org/r/20201009220524.485102-2-axelrasmussen@google.com



Acked-by: Michel Lespinasse <walken@google.com>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Axel Rasmussen <axelrasmussen@google.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

parent 81ff92a9

kernel/trace/trace_events_synth.c

+4 −0

Original line number	Diff line number	Diff line
		@@ -229,6 +229,8 @@ static int synth_field_size(char *type)
		size = sizeof(long);
		else if (strcmp(type, "unsigned long") == 0)
		size = sizeof(unsigned long);
		else if (strcmp(type, "bool") == 0)
		size = sizeof(bool);
		else if (strcmp(type, "pid_t") == 0)
		size = sizeof(pid_t);
		else if (strcmp(type, "gfp_t") == 0)
		@@ -271,6 +273,8 @@ static const char synth_field_fmt(char type)
		fmt = "%ld";
		else if (strcmp(type, "unsigned long") == 0)
		fmt = "%lu";
		else if (strcmp(type, "bool") == 0)
		fmt = "%d";
		else if (strcmp(type, "pid_t") == 0)
		fmt = "%d";
		else if (strcmp(type, "gfp_t") == 0)

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