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authorAxel Rasmussen <axelrasmussen@google.com>2020-10-09 15:05:23 -0700
committerSteven Rostedt (VMware) <rostedt@goodmis.org>2020-10-15 12:01:14 -0400
commit6107742d15832011cd0396d821f3225b52551f1f (patch)
tree3a4e9b08918430a366a89ccf92bcc44492ceea44 /kernel
parent81ff92a93d954efa29e1d514934d6a47cd5f4558 (diff)
downloadlinux-6107742d15832011cd0396d821f3225b52551f1f.tar.gz
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>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/trace/trace_events_synth.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/kernel/trace/trace_events_synth.c b/kernel/trace/trace_events_synth.c
index d239f0e2af8f..3212e2c653b3 100644
--- a/kernel/trace/trace_events_synth.c
+++ b/kernel/trace/trace_events_synth.c
@@ -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)