1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
|
/*
* hangcheck-timer.c
*
* Driver for a little io fencing timer.
*
* Copyright (C) 2002, 2003 Oracle. All rights reserved.
*
* Author: Joel Becker <joel.becker@oracle.com>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public
* License version 2 as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public
* License along with this program; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 021110-1307, USA.
*/
/*
* The hangcheck-timer driver uses the TSC to catch delays that
* jiffies does not notice. A timer is set. When the timer fires, it
* checks whether it was delayed and if that delay exceeds a given
* margin of error. The hangcheck_tick module parameter takes the timer
* duration in seconds. The hangcheck_margin parameter defines the
* margin of error, in seconds. The defaults are 60 seconds for the
* timer and 180 seconds for the margin of error. IOW, a timer is set
* for 60 seconds. When the timer fires, the callback checks the
* actual duration that the timer waited. If the duration exceeds the
* allotted time and margin (here 60 + 180, or 240 seconds), the machine
* is restarted. A healthy machine will have the duration match the
* expected timeout very closely.
*/
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/mm.h>
#include <linux/reboot.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/uaccess.h>
#include <linux/sysrq.h>
#include <linux/timer.h>
#include <linux/hrtimer.h>
#define VERSION_STR "0.9.1"
#define DEFAULT_IOFENCE_MARGIN 60 /* Default fudge factor, in seconds */
#define DEFAULT_IOFENCE_TICK 180 /* Default timer timeout, in seconds */
static int hangcheck_tick = DEFAULT_IOFENCE_TICK;
static int hangcheck_margin = DEFAULT_IOFENCE_MARGIN;
static int hangcheck_reboot; /* Defaults to not reboot */
static int hangcheck_dump_tasks; /* Defaults to not dumping SysRQ T */
/* options - modular */
module_param(hangcheck_tick, int, 0);
MODULE_PARM_DESC(hangcheck_tick, "Timer delay.");
module_param(hangcheck_margin, int, 0);
MODULE_PARM_DESC(hangcheck_margin, "If the hangcheck timer has been delayed more than hangcheck_margin seconds, the driver will fire.");
module_param(hangcheck_reboot, int, 0);
MODULE_PARM_DESC(hangcheck_reboot, "If nonzero, the machine will reboot when the timer margin is exceeded.");
module_param(hangcheck_dump_tasks, int, 0);
MODULE_PARM_DESC(hangcheck_dump_tasks, "If nonzero, the machine will dump the system task state when the timer margin is exceeded.");
MODULE_AUTHOR("Oracle");
MODULE_DESCRIPTION("Hangcheck-timer detects when the system has gone out to lunch past a certain margin.");
MODULE_LICENSE("GPL");
MODULE_VERSION(VERSION_STR);
/* options - nonmodular */
#ifndef MODULE
static int __init hangcheck_parse_tick(char *str)
{
int par;
if (get_option(&str,&par))
hangcheck_tick = par;
return 1;
}
static int __init hangcheck_parse_margin(char *str)
{
int par;
if (get_option(&str,&par))
hangcheck_margin = par;
return 1;
}
static int __init hangcheck_parse_reboot(char *str)
{
int par;
if (get_option(&str,&par))
hangcheck_reboot = par;
return 1;
}
static int __init hangcheck_parse_dump_tasks(char *str)
{
int par;
if (get_option(&str,&par))
hangcheck_dump_tasks = par;
return 1;
}
__setup("hcheck_tick", hangcheck_parse_tick);
__setup("hcheck_margin", hangcheck_parse_margin);
__setup("hcheck_reboot", hangcheck_parse_reboot);
__setup("hcheck_dump_tasks", hangcheck_parse_dump_tasks);
#endif /* not MODULE */
#define TIMER_FREQ 1000000000ULL
/* Last time scheduled */
static unsigned long long hangcheck_tsc, hangcheck_tsc_margin;
static void hangcheck_fire(unsigned long);
static DEFINE_TIMER(hangcheck_ticktock, hangcheck_fire);
static void hangcheck_fire(unsigned long data)
{
unsigned long long cur_tsc, tsc_diff;
cur_tsc = ktime_get_ns();
if (cur_tsc > hangcheck_tsc)
tsc_diff = cur_tsc - hangcheck_tsc;
else
tsc_diff = (cur_tsc + (~0ULL - hangcheck_tsc)); /* or something */
if (tsc_diff > hangcheck_tsc_margin) {
if (hangcheck_dump_tasks) {
printk(KERN_CRIT "Hangcheck: Task state:\n");
#ifdef CONFIG_MAGIC_SYSRQ
handle_sysrq('t');
#endif /* CONFIG_MAGIC_SYSRQ */
}
if (hangcheck_reboot) {
printk(KERN_CRIT "Hangcheck: hangcheck is restarting the machine.\n");
emergency_restart();
} else {
printk(KERN_CRIT "Hangcheck: hangcheck value past margin!\n");
}
}
#if 0
/*
* Enable to investigate delays in detail
*/
printk("Hangcheck: called %Ld ns since last time (%Ld ns overshoot)\n",
tsc_diff, tsc_diff - hangcheck_tick*TIMER_FREQ);
#endif
mod_timer(&hangcheck_ticktock, jiffies + (hangcheck_tick*HZ));
hangcheck_tsc = ktime_get_ns();
}
static int __init hangcheck_init(void)
{
printk("Hangcheck: starting hangcheck timer %s (tick is %d seconds, margin is %d seconds).\n",
VERSION_STR, hangcheck_tick, hangcheck_margin);
hangcheck_tsc_margin =
(unsigned long long)hangcheck_margin + hangcheck_tick;
hangcheck_tsc_margin *= TIMER_FREQ;
hangcheck_tsc = ktime_get_ns();
mod_timer(&hangcheck_ticktock, jiffies + (hangcheck_tick*HZ));
return 0;
}
static void __exit hangcheck_exit(void)
{
del_timer_sync(&hangcheck_ticktock);
printk("Hangcheck: Stopped hangcheck timer.\n");
}
module_init(hangcheck_init);
module_exit(hangcheck_exit);
|
