From: Liu Hua <sdu.liu@xxxxxxxxxx>
Subject: hung_task: check the value of "sysctl_hung_task_timeout_sec"
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 :
[ 205.452934] 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.liu@xxxxxxxxxx>
Tested-by: Satoru Takeuchi <satoru.takeuchi@xxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx> [3.4+]
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
Documentation/sysctl/kernel.txt | 1 +
kernel/sysctl.c | 6 ++++++
2 files changed, 7 insertions(+)
diff -puN Documentation/sysctl/kernel.txt~hung_task-check-the-value-of-sysctl_hung_task_timeout_sec Documentation/sysctl/kernel.txt
--- a/Documentation/sysctl/kernel.txt~hung_task-check-the-value-of-sysctl_hung_task_timeout_sec
+++ a/Documentation/sysctl/kernel.txt
@@ -317,6 +317,7 @@ for more than this value report a warnin
This file shows up if CONFIG_DETECT_HUNG_TASK is enabled.
0: means infinite timeout - no checking done.
+Possible values to set are in range {0..LONG_MAX/HZ}.
==============================================================
diff -puN kernel/sysctl.c~hung_task-check-the-value-of-sysctl_hung_task_timeout_sec kernel/sysctl.c
--- a/kernel/sysctl.c~hung_task-check-the-value-of-sysctl_hung_task_timeout_sec
+++ a/kernel/sysctl.c
@@ -141,6 +141,11 @@ 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
@@ -985,6 +990,7 @@ 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",
_
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