[tip:perf/core] watchdog: Disallow setting watchdog_thresh to -1

[tip-bot for Li Zefan <tipbot@zytor.com>]

Commit-ID:  a6572f84c5b135d9b6df279ed3c8de028bd1edd9
Gitweb:     http://git.kernel.org/tip/a6572f84c5b135d9b6df279ed3c8de028bd1edd9
Author:     Li Zefan <lizefan@huawei.com>
AuthorDate: Fri, 17 May 2013 10:31:04 +0800
Committer:  Ingo Molnar <mingo@kernel.org>
CommitDate: Tue, 28 May 2013 11:28:18 +0200

watchdog: Disallow setting watchdog_thresh to -1

In old kernels, it's allowed to set softlockup_thresh to -1 or 0
to disable softlockup detection. However watchdog_thresh only
uses 0 to disable detection, and setting it to -1 just froze my
box and nothing I can do but reboot.

Signed-off-by: Li Zefan <lizefan@huawei.com>
Acked-by: Don Zickus <dzickus@redhat.com>
Link: http://lkml.kernel.org/r/51959668.9040106@huawei.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 kernel/sysctl.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 9edcf45..b0a1f99 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -120,7 +120,6 @@ extern int blk_iopoll_enabled;
 /* Constants used for minimum and  maximum */
 #ifdef CONFIG_LOCKUP_DETECTOR
 static int sixty = 60;
-static int neg_one = -1;
 #endif
 
 static int zero;
@@ -814,7 +813,7 @@ static struct ctl_table kern_table[] = {
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
 		.proc_handler	= proc_dowatchdog,
-		.extra1		= &neg_one,
+		.extra1		= &zero,
 		.extra2		= &sixty,
 	},
 	{