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Commit 80df2847 authored by Liu Hua's avatar Liu Hua Committed by Linus Torvalds
Browse files

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 :

  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: default avatarLiu Hua <sdu.liu@huawei.com>
Tested-by: default avatarSatoru Takeuchi <satoru.takeuchi@gmail.com>
Cc: <stable@vger.kernel.org>	[3.4+]
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 2aaf308b

Documentation/sysctl/kernel.txt

+1 −0
Original line number Diff line number Diff line
@@ -317,6 +317,7 @@ for more than this value report a warning. 
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}.



==============================================================

kernel/sysctl.c

+6 −0
Original line number Diff line number Diff line
@@ -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",