3.13.11.1 -stable review patch.  If anyone has any objections, please let me 
know.

------------------

From: Liu Hua <sdu....@huawei.com>

commit 80df28476505ed4e6701c3448c63c9229a50c655 upstream.

As sysctl_hung_task_timeout_sec is unsigned long, when this value is
larger then LONG_MAX/HZ, the function schedule_timeout_interruptible in
watchdog will return immediately without sleep and with print :

  schedule_timeout: wrong timeout value ffffffffffffff83

and then the funtion watchdog will call schedule_timeout_interruptible
again and again.  The screen will be filled with

        "schedule_timeout: wrong timeout value ffffffffffffff83"

This patch does some check and correction in sysctl, to let the function
schedule_timeout_interruptible allways get the valid parameter.

Signed-off-by: Liu Hua <sdu....@huawei.com>
Tested-by: Satoru Takeuchi <satoru.takeu...@gmail.com>
Signed-off-by: Andrew Morton <a...@linux-foundation.org>
Signed-off-by: Linus Torvalds <torva...@linux-foundation.org>
Signed-off-by: Kamal Mostafa <ka...@canonical.com>
---
 kernel/sysctl.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 06962ba..fcdced1 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -143,6 +143,11 @@ static int min_percpu_pagelist_fract = 8;
 static int ngroups_max = NGROUPS_MAX;
 static const int cap_last_cap = CAP_LAST_CAP;
 
+/*this is needed for proc_doulongvec_minmax of sysctl_hung_task_timeout_secs */
+#ifdef CONFIG_DETECT_HUNG_TASK
+static unsigned long hung_task_timeout_max = (LONG_MAX/HZ);
+#endif
+
 #ifdef CONFIG_INOTIFY_USER
 #include <linux/inotify.h>
 #endif
@@ -989,6 +994,7 @@ static struct ctl_table kern_table[] = {
                .maxlen         = sizeof(unsigned long),
                .mode           = 0644,
                .proc_handler   = proc_dohung_task_timeout_secs,
+               .extra2         = &hung_task_timeout_max,
        },
        {
                .procname       = "hung_task_warnings",
-- 
1.9.1

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