Re: [kernel-hardening] [PATCH v4 3/8] param: convert some "on"/"off" users to strtobool

[David Brown]

On Tue, Jan 19, 2016 at 10:08:37AM -0800, Kees Cook wrote:

> diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
> index 9cc20af58c76..f5ea98490ffa 100644
> --- a/kernel/time/tick-sched.c
> +++ b/kernel/time/tick-sched.c
> @@ -387,20 +388,14 @@ void __init tick_nohz_init(void)
> /*
>  * NO HZ enabled ?
>  */
> -static int tick_nohz_enabled __read_mostly  = 1;
> +static bool tick_nohz_enabled __read_mostly  = true;
> unsigned long tick_nohz_active  __read_mostly;
> /*
>  * Enable / Disable tickless mode
>  */

Just discovered this conflicts with a recent patch with
CONFIG_NO_HZ_COMMON:

	commit 46373a15f65fe862f31c19a484acdf551f2b442f
	Author: Jean Delvare <jdelvare@xxxxxxx>
	Date:   Mon Jan 11 17:40:31 2016 +0100

	    time: nohz: Expose tick_nohz_enabled

kernel/time/tick-sched.c:390:6: error: conflicting types for âtick_nohz_enabledâ
	bool tick_nohz_enabled __read_mostly = true;
	     ^
In file included from kernel/time/tick-internal.h:5:0,
                from kernel/time/tick-sched.c:30:
include/linux/tick.h:101:12: note: previous declaration of âtick_nohz_enabledâ was here
	extern int tick_nohz_enabled;
	           ^

Fixing the compilation error, it compiles and boots on arm64, however
it isn't detecting the write (with the lkdtm test).  I'll continue
looking into what's preventing this.

David