[PATCH tip/core/rcu 08/13] rcutorture: Place event-traced strings into trace buffer

[Paul E. McKenney]

Strings used in event tracing need to be specially handled, for example,
being copied to the trace buffer instead of being pointed to by the trace
buffer.  Although the TPS() macro can be used to "launder" pointed-to
strings, this might not be all that effective within a loadable module.
This commit therefore copies rcutorture's strings to the trace buffer.

Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>

Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
---
 include/trace/events/rcu.h                                 | 7 +++++--
 kernel/rcu/rcutorture.c                                    | 2 +-
 tools/testing/selftests/rcutorture/configs/rcu/BUSTED.boot | 2 +-
 3 files changed, 7 insertions(+), 4 deletions(-)

diff --git a/include/trace/events/rcu.h b/include/trace/events/rcu.h
index 91dc089d65b7..e91ae1f2290d 100644
--- a/include/trace/events/rcu.h
+++ b/include/trace/events/rcu.h
@@ -703,6 +703,7 @@ TRACE_EVENT(rcu_batch_end,
  * at the beginning and end of the read, respectively.  Note that the
  * callback address can be NULL.
  */
+#define RCUTORTURENAME_LEN 8
 TRACE_EVENT(rcu_torture_read,
 
 	TP_PROTO(const char *rcutorturename, struct rcu_head *rhp,
@@ -711,7 +712,7 @@ TRACE_EVENT(rcu_torture_read,
 	TP_ARGS(rcutorturename, rhp, secs, c_old, c),
 
 	TP_STRUCT__entry(
-		__field(const char *, rcutorturename)
+		__field(char, rcutorturename[RCUTORTURENAME_LEN])
 		__field(struct rcu_head *, rhp)
 		__field(unsigned long, secs)
 		__field(unsigned long, c_old)
@@ -719,7 +720,9 @@ TRACE_EVENT(rcu_torture_read,
 	),
 
 	TP_fast_assign(
-		__entry->rcutorturename = rcutorturename;
+		strncpy(__entry->rcutorturename, rcutorturename,
+			RCUTORTURENAME_LEN);
+		__entry->rcutorturename[RCUTORTURENAME_LEN - 1] = 0;
 		__entry->rhp = rhp;
 		__entry->secs = secs;
 		__entry->c_old = c_old;
diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c
index 8d59c82bec0b..b48d2107f176 100644
--- a/kernel/rcu/rcutorture.c
+++ b/kernel/rcu/rcutorture.c
@@ -496,7 +496,7 @@ static struct rcu_torture_ops rcu_busted_ops = {
 	.fqs		= NULL,
 	.stats		= NULL,
 	.irq_capable	= 1,
-	.name		= "rcu_busted"
+	.name		= "busted"
 };
 
 /*
diff --git a/tools/testing/selftests/rcutorture/configs/rcu/BUSTED.boot b/tools/testing/selftests/rcutorture/configs/rcu/BUSTED.boot
index 6804f9dcfc1b..be7728db42fd 100644
--- a/tools/testing/selftests/rcutorture/configs/rcu/BUSTED.boot
+++ b/tools/testing/selftests/rcutorture/configs/rcu/BUSTED.boot
@@ -1 +1 @@
-rcutorture.torture_type=rcu_busted
+rcutorture.torture_type=busted
-- 
2.5.2