From: Sri Krishna chowdary <[email protected]>
Kmemleak scan is cpu intensive and can stall user tasks at times.
To prevent this, add config DEBUG_KMEMLEAK_SCAN_ON to enable/disable
auto scan on boot up.
Also protect first_run with CONFIG_DEBUG_KMEMLEAK_SCAN_ON 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]>
---
lib/Kconfig.debug | 11 +++++++++++
mm/kmemleak.c | 6 ++++++
2 files changed, 17 insertions(+)
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index e5e7c03..9542852 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -593,6 +593,17 @@ 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_SCAN_ON
+ bool "Enable kmemleak auto scan thread on boot up"
+ default y
+ depends on DEBUG_KMEMLEAK
+ help
+ Kmemleak scan is 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.
+
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..ac53678 100644
--- a/mm/kmemleak.c
+++ b/mm/kmemleak.c
@@ -1647,11 +1647,14 @@ static void kmemleak_scan(void)
*/
static int kmemleak_scan_thread(void *arg)
{
+#ifdef CONFIG_DEBUG_KMEMLEAK_SCAN_ON
static int first_run = 1;
+#endif
pr_info("Automatic memory scanning thread started\n");
set_user_nice(current, 10);
+#ifdef CONFIG_DEBUG_KMEMLEAK_SCAN_ON
/*
* Wait before the first scan to allow the system to fully initialize.
*/
@@ -1661,6 +1664,7 @@ static int kmemleak_scan_thread(void *arg)
while (timeout && !kthread_should_stop())
timeout = schedule_timeout_interruptible(timeout);
}
+#endif
while (!kthread_should_stop()) {
signed long timeout = jiffies_scan_wait;
@@ -2141,9 +2145,11 @@ static int __init kmemleak_late_init(void)
return -ENOMEM;
}
+#ifdef CONFIG_DEBUG_KMEMLEAK_SCAN_ON
mutex_lock(&scan_mutex);
start_scan_thread();
mutex_unlock(&scan_mutex);
+#endif
pr_info("Kernel memory leak detector initialized\n");
--
2.1.4
On Wed, Oct 17, 2018 at 01:33:28PM +0530, Prateek Patel wrote:
> diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
> index e5e7c03..9542852 100644
> --- a/lib/Kconfig.debug
> +++ b/lib/Kconfig.debug
> @@ -593,6 +593,17 @@ 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_SCAN_ON
Nitpick: DEBUG_KMEMLEAK_AUTO_SCAN may be a better name since you don't
aim to disable scanning altogether.
> + bool "Enable kmemleak auto scan thread on boot up"
> + default y
> + depends on DEBUG_KMEMLEAK
> + help
> + Kmemleak scan is cpu intensive and can stall user tasks at times.
I guess that depends on the CPU.
> + This option enables/disables automatic kmemleak scan at boot up.
> +
> + Say N here to disable kmemleak auto scan thread to stop automatic
> + scanning.
You should also mention that disabling this option also disables
automatic reporting of memory leaks. And I'd add a "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..ac53678 100644
> --- a/mm/kmemleak.c
> +++ b/mm/kmemleak.c
> @@ -1647,11 +1647,14 @@ static void kmemleak_scan(void)
> */
> static int kmemleak_scan_thread(void *arg)
> {
> +#ifdef CONFIG_DEBUG_KMEMLEAK_SCAN_ON
> static int first_run = 1;
> +#endif
static int first_run = IS_ENABLED(CONFIG_DEBUG_KMEMLEAK_AUTO_SCAN);
>
> pr_info("Automatic memory scanning thread started\n");
> set_user_nice(current, 10);
>
> +#ifdef CONFIG_DEBUG_KMEMLEAK_SCAN_ON
> /*
> * Wait before the first scan to allow the system to fully initialize.
> */
> @@ -1661,6 +1664,7 @@ static int kmemleak_scan_thread(void *arg)
> while (timeout && !kthread_should_stop())
> timeout = schedule_timeout_interruptible(timeout);
> }
> +#endif
With the first_run change above, this #ifdef is no longer needed.
>
> while (!kthread_should_stop()) {
> signed long timeout = jiffies_scan_wait;
> @@ -2141,9 +2145,11 @@ static int __init kmemleak_late_init(void)
> return -ENOMEM;
> }
>
> +#ifdef CONFIG_DEBUG_KMEMLEAK_SCAN_ON
> mutex_lock(&scan_mutex);
> start_scan_thread();
> mutex_unlock(&scan_mutex);
> +#endif
Please use:
if (IS_ENABLED(CONFIG_DEBUG_KMEMLEAK_AUTO_SCAN)) {
...
}
--
Catalin