[PATCH] rcu: define tracepoint strings only if CONFIG_TRACING is set

From: Ard Biesheuvel
Date: Fri Jul 11 2014 - 07:38:30 EST


Commit f7f7bac9cb1c ("rcu: Have the RCU tracepoints use the tracepoint_string
infrastructure") unconditionally populates the __tracepoint_str input section,
but this section is not assigned an output section if CONFIG_TRACING is not set.
This results in the __tracepoint_str turning up in unexpected places, i.e.,
after _edata.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
Cc: rostedt@xxxxxxxxxxx
Cc: dipankar@xxxxxxxxxx
Cc: paulmck@xxxxxxxxxxxxxxxxxx
---
kernel/rcu/tree.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index f1ba77363fbb..ac1984149eb5 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -79,9 +79,16 @@ static struct lock_class_key rcu_fqs_class[RCU_NUM_LVLS];
* the tracing userspace tools to be able to decipher the string
* address to the matching string.
*/
+#ifdef CONFIG_TRACING
+#define DEFINE_TPS(sname) \
+static const char *tp_##sname##_varname __used __tracepoint_string = sname##_varname;
+#else
+#define DEFINE_TPS(sname)
+#endif
+
#define RCU_STATE_INITIALIZER(sname, sabbr, cr) \
static char sname##_varname[] = #sname; \
-static const char *tp_##sname##_varname __used __tracepoint_string = sname##_varname; \
+DEFINE_TPS(sname) \
struct rcu_state sname##_state = { \
.level = { &sname##_state.node[0] }, \
.call = cr, \
--
1.8.3.2

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