patches/old/mm-kfence-print-disabling-or-re-enabling-message.patch

From: Jackie Liu <liuyun01@kylinos.cn>
Subject: mm/kfence: print disabling or re-enabling message
Date: Wed, 18 May 2022 15:31:05 +0800

By printing information, we can friendly prompt the status change
information of kfence by dmesg and record by syslog.

Also, set kfence_enabled to false only when needed.

Link: https://lkml.kernel.org/r/20220518073105.3160335-1-liu.yun@linux.dev
Signed-off-by: Jackie Liu <liuyun01@kylinos.cn>
Co-developed-by: Marco Elver <elver@google.com>
Signed-off-by: Marco Elver <elver@google.com>
Reviewed-by: Marco Elver <elver@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/kfence/core.c |    6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

--- a/mm/kfence/core.c~mm-kfence-print-disabling-or-re-enabling-message
+++ a/mm/kfence/core.c
@@ -69,8 +69,11 @@ static int param_set_sample_interval(con
 	if (ret < 0)
 		return ret;
 
-	if (!num) /* Using 0 to indicate KFENCE is disabled. */
+	/* Using 0 to indicate KFENCE is disabled. */
+	if (!num && READ_ONCE(kfence_enabled)) {
+		pr_info("disabled\n");
 		WRITE_ONCE(kfence_enabled, false);
+	}
 
 	*((unsigned long *)kp->arg) = num;
 
@@ -898,6 +901,7 @@ static int kfence_enable_late(void)
 
 	WRITE_ONCE(kfence_enabled, true);
 	queue_delayed_work(system_unbound_wq, &kfence_timer, 0);
+	pr_info("re-enabled\n");
 	return 0;
 }
 
_