From: Sri Krishna chowdary <[email protected]>

Kmemleak scan can be cpu intensive and can stall user tasks at times.
To prevent this, add config DEBUG_KMEMLEAK_AUTO_SCAN to enable/disable
auto scan on boot up.
Also protect first_run with DEBUG_KMEMLEAK_AUTO_SCAN as this is meant
for only first automatic scan.

Signed-off-by: Sri Krishna chowdary <[email protected]>
Signed-off-by: Sachin Nikam <[email protected]>
Signed-off-by: Prateek <[email protected]>
---
v2:
* change config name to DEBUG_KMEMLEAK_AUTO_SCAN from DEBUG_KMEMLEAK_SCAN_ON
* use IS_ENABLED(...) instead of #ifdef ...
* update commit message according to config name
---
 lib/Kconfig.debug | 15 +++++++++++++++
 mm/kmemleak.c     | 10 ++++++----
 2 files changed, 21 insertions(+), 4 deletions(-)

diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index c958013..a14166d 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -593,6 +593,21 @@ config DEBUG_KMEMLEAK_DEFAULT_OFF
          Say Y here to disable kmemleak by default. It can then be enabled
          on the command line via kmemleak=on.
 
+config DEBUG_KMEMLEAK_AUTO_SCAN
+       bool "Enable kmemleak auto scan thread on boot up"
+       default y
+       depends on DEBUG_KMEMLEAK
+       help
+         Depending on the cpu, kmemleak scan may be cpu intensive and can
+         stall user tasks at times. This option enables/disables automatic
+         kmemleak scan at boot up.
+
+         Say N here to disable kmemleak auto scan thread to stop automatic
+         scanning. Disabling this option disables automatic reporting of
+         memory leaks.
+
+         If unsure, say Y.
+
 config DEBUG_STACK_USAGE
        bool "Stack utilization instrumentation"
        depends on DEBUG_KERNEL && !IA64
diff --git a/mm/kmemleak.c b/mm/kmemleak.c
index 877de4f..a614930 100644
--- a/mm/kmemleak.c
+++ b/mm/kmemleak.c
@@ -1647,7 +1647,7 @@ static void kmemleak_scan(void)
  */
 static int kmemleak_scan_thread(void *arg)
 {
-       static int first_run = 1;
+       static int first_run = IS_ENABLED(CONFIG_DEBUG_KMEMLEAK_AUTO_SCAN);
 
        pr_info("Automatic memory scanning thread started\n");
        set_user_nice(current, 10);
@@ -2141,9 +2141,11 @@ static int __init kmemleak_late_init(void)
                return -ENOMEM;
        }
 
-       mutex_lock(&scan_mutex);
-       start_scan_thread();
-       mutex_unlock(&scan_mutex);
+       if (IS_ENABLED(CONFIG_DEBUG_KMEMLEAK_AUTO_SCAN)) {
+               mutex_lock(&scan_mutex);
+               start_scan_thread();
+               mutex_unlock(&scan_mutex);
+       }
 
        pr_info("Kernel memory leak detector initialized\n");
 
-- 
2.1.4

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