[tip: locking/core] kcsan: Show message if enabled early

[tip-bot2 for Marco Elver]

The following commit has been merged into the locking/core branch of tip:

Commit-ID:     2778793072c31e3eb33842f3bd7da82dfc7efc6b
Gitweb:        https://git.kernel.org/tip/2778793072c31e3eb33842f3bd7da82dfc7efc6b
Author:        Marco Elver <elver@xxxxxxxxxx>
AuthorDate:    Fri, 31 Jul 2020 10:17:22 +02:00
Committer:     Paul E. McKenney <paulmck@xxxxxxxxxx>
CommitterDate: Mon, 24 Aug 2020 15:10:22 -07:00

kcsan: Show message if enabled early

Show a message in the kernel log if KCSAN was enabled early.

Signed-off-by: Marco Elver <elver@xxxxxxxxxx>
Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxx>
---
 kernel/kcsan/core.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/kernel/kcsan/core.c b/kernel/kcsan/core.c
index 99e5044..b176400 100644
--- a/kernel/kcsan/core.c
+++ b/kernel/kcsan/core.c
@@ -1,5 +1,7 @@
 // SPDX-License-Identifier: GPL-2.0
 
+#define pr_fmt(fmt) "kcsan: " fmt
+
 #include <linux/atomic.h>
 #include <linux/bug.h>
 #include <linux/delay.h>
@@ -463,7 +465,7 @@ kcsan_setup_watchpoint(const volatile void *ptr, size_t size, int type)
 
 	if (IS_ENABLED(CONFIG_KCSAN_DEBUG)) {
 		kcsan_disable_current();
-		pr_err("KCSAN: watching %s, size: %zu, addr: %px [slot: %d, encoded: %lx]\n",
+		pr_err("watching %s, size: %zu, addr: %px [slot: %d, encoded: %lx]\n",
 		       is_write ? "write" : "read", size, ptr,
 		       watchpoint_slot((unsigned long)ptr),
 		       encode_watchpoint((unsigned long)ptr, size, is_write));
@@ -623,8 +625,10 @@ void __init kcsan_init(void)
 	 * We are in the init task, and no other tasks should be running;
 	 * WRITE_ONCE without memory barrier is sufficient.
 	 */
-	if (kcsan_early_enable)
+	if (kcsan_early_enable) {
+		pr_info("enabled early\n");
 		WRITE_ONCE(kcsan_enabled, true);
+	}
 }
 
 /* === Exported interface =================================================== */