rcutorture: Place event-traced strings into trace buffer

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@linux.vnet.ibm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>

diff --git a/include/trace/events/rcu.h b/include/trace/events/rcu.h
index 91dc089..e91ae1f 100644 (file)
--- 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 8d59c82..b48d210 100644 (file)
--- 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 6804f9d..be7728d 100644 (file)
--- 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