How to display printk messages filtered by level as they come?
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2
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I wrote a hello word module that performs a printk when it is loaded in level ALERT and another printk when it is released with level INFO:
#include <linux/module.h>
#include <linux/kernel.h>
MODULE_LICENSE("GPL");
static int init_hello(void)
{
printk(KERN_ALERT "init called in hellon");
return 0;
}
static void cleanup_hello(void)
{
printk(KERN_INFO "cleanup called in hellon");
}
module_init(init_hello);
module_exit(cleanup_hello);
Then I was trying to filter the kernel messages by its level, I did that using dmesg -l , but I want to see the messages as they appear, so I was using
tail -f /var/log/kern.log
Using this command I can see the messages, but how can I filter the messages by level?
I am using Ubuntu 14.04 with kernel 3.16.4
I then tried to print the messages to the console using:
echo 7 7 7 7 > /proc/sys/kernel/printk
But it doesn't print any message to the console. I tried to set the console-level using dmesg -n alert, but it doesn't work either, thus I am not sure what setting the console-level by dmesg or /proc/sys/kernel/printk does.
How can I use these levels efficiently?
Thanks for your help
kernel linux-kernel kernel-modules debugging
asked Oct 9 '14 at 20:37
Lilás
1114
add a comment |
up vote
2
down vote
favorite
I wrote a hello word module that performs a printk when it is loaded in level ALERT and another printk when it is released with level INFO:
#include <linux/module.h>
#include <linux/kernel.h>
MODULE_LICENSE("GPL");
static int init_hello(void)
{
printk(KERN_ALERT "init called in hellon");
return 0;
}
static void cleanup_hello(void)
{
printk(KERN_INFO "cleanup called in hellon");
}
module_init(init_hello);
module_exit(cleanup_hello);
Then I was trying to filter the kernel messages by its level, I did that using dmesg -l , but I want to see the messages as they appear, so I was using
tail -f /var/log/kern.log
Using this command I can see the messages, but how can I filter the messages by level?
I am using Ubuntu 14.04 with kernel 3.16.4
I then tried to print the messages to the console using:
echo 7 7 7 7 > /proc/sys/kernel/printk
But it doesn't print any message to the console. I tried to set the console-level using dmesg -n alert, but it doesn't work either, thus I am not sure what setting the console-level by dmesg or /proc/sys/kernel/printk does.
How can I use these levels efficiently?
Thanks for your help
kernel linux-kernel kernel-modules debugging
asked Oct 9 '14 at 20:37
Lilás
1114
The items in/procare device pointers and setters. They are not files. Welcome!!!
– eyoung100
Oct 9 '14 at 20:46
Yes, of course, I will change the text, but you got what I meant :)
– Lilás
Oct 9 '14 at 20:56
add a comment |
up vote
2
down vote
favorite
up vote
2
down vote
favorite
I wrote a hello word module that performs a printk when it is loaded in level ALERT and another printk when it is released with level INFO:
#include <linux/module.h>
#include <linux/kernel.h>
MODULE_LICENSE("GPL");
static int init_hello(void)
{
printk(KERN_ALERT "init called in hellon");
return 0;
}
static void cleanup_hello(void)
{
printk(KERN_INFO "cleanup called in hellon");
}
module_init(init_hello);
module_exit(cleanup_hello);
Then I was trying to filter the kernel messages by its level, I did that using dmesg -l , but I want to see the messages as they appear, so I was using
tail -f /var/log/kern.log
Using this command I can see the messages, but how can I filter the messages by level?
I am using Ubuntu 14.04 with kernel 3.16.4
I then tried to print the messages to the console using:
echo 7 7 7 7 > /proc/sys/kernel/printk
But it doesn't print any message to the console. I tried to set the console-level using dmesg -n alert, but it doesn't work either, thus I am not sure what setting the console-level by dmesg or /proc/sys/kernel/printk does.
How can I use these levels efficiently?
Thanks for your help
kernel linux-kernel kernel-modules debugging
asked Oct 9 '14 at 20:37
Lilás
1114
I wrote a hello word module that performs a printk when it is loaded in level ALERT and another printk when it is released with level INFO:
#include <linux/module.h>
#include <linux/kernel.h>
MODULE_LICENSE("GPL");
static int init_hello(void)
{
printk(KERN_ALERT "init called in hellon");
return 0;
}
static void cleanup_hello(void)
{
printk(KERN_INFO "cleanup called in hellon");
}
module_init(init_hello);
module_exit(cleanup_hello);
Then I was trying to filter the kernel messages by its level, I did that using dmesg -l , but I want to see the messages as they appear, so I was using
tail -f /var/log/kern.log
Using this command I can see the messages, but how can I filter the messages by level?
I am using Ubuntu 14.04 with kernel 3.16.4
I then tried to print the messages to the console using:
echo 7 7 7 7 > /proc/sys/kernel/printk
But it doesn't print any message to the console. I tried to set the console-level using dmesg -n alert, but it doesn't work either, thus I am not sure what setting the console-level by dmesg or /proc/sys/kernel/printk does.
How can I use these levels efficiently?
Thanks for your help
kernel linux-kernel kernel-modules debugging
kernel linux-kernel kernel-modules debugging
asked Oct 9 '14 at 20:37
Lilás
1114
asked Oct 9 '14 at 20:37
Lilás
1114
edited Oct 9 '14 at 21:03
asked Oct 9 '14 at 20:37
Lilás
1114
asked Oct 9 '14 at 20:37
Lilás
1114
asked Oct 9 '14 at 20:37
Lilás
1114
1114
The items in/procare device pointers and setters. They are not files. Welcome!!!
– eyoung100
Oct 9 '14 at 20:46
Yes, of course, I will change the text, but you got what I meant :)
– Lilás
Oct 9 '14 at 20:56
add a comment |
The items in/procare device pointers and setters. They are not files. Welcome!!!
– eyoung100
Oct 9 '14 at 20:46
Yes, of course, I will change the text, but you got what I meant :)
– Lilás
Oct 9 '14 at 20:56
The items in
/proc are device pointers and setters. They are not files. Welcome!!!– eyoung100
Oct 9 '14 at 20:46
The items in
/proc are device pointers and setters. They are not files. Welcome!!!– eyoung100
Oct 9 '14 at 20:46
Yes, of course, I will change the text, but you got what I meant :)
– Lilás
Oct 9 '14 at 20:56
Yes, of course, I will change the text, but you got what I meant :)
– Lilás
Oct 9 '14 at 20:56
add a comment |
1 Answer
1
active
oldest
votes
up vote
0
down vote
On Ubuntu 16.04, util-linux 2.27.1, you can do:
dmesg --level err,warn --raw -w
where:
-wfollows the messages as they come
--levelrestricts which levels will show
--rawshows the level at the beginning of the message e.g. as<3>
answered May 22 at 12:05
Ciro Santilli 新疆改造中心 六四事件 法轮功
4,84324039
add a comment |
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1 Answer
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1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
0
down vote
On Ubuntu 16.04, util-linux 2.27.1, you can do:
dmesg --level err,warn --raw -w
where:
-wfollows the messages as they come
--levelrestricts which levels will show
--rawshows the level at the beginning of the message e.g. as<3>
answered May 22 at 12:05
Ciro Santilli 新疆改造中心 六四事件 法轮功
4,84324039
add a comment |
up vote
0
down vote
On Ubuntu 16.04, util-linux 2.27.1, you can do:
dmesg --level err,warn --raw -w
where:
-wfollows the messages as they come
--levelrestricts which levels will show
--rawshows the level at the beginning of the message e.g. as<3>
answered May 22 at 12:05
Ciro Santilli 新疆改造中心 六四事件 法轮功
4,84324039
add a comment |
up vote
0
down vote
up vote
0
down vote
On Ubuntu 16.04, util-linux 2.27.1, you can do:
dmesg --level err,warn --raw -w
where:
-wfollows the messages as they come
--levelrestricts which levels will show
--rawshows the level at the beginning of the message e.g. as<3>
answered May 22 at 12:05
Ciro Santilli 新疆改造中心 六四事件 法轮功
4,84324039
On Ubuntu 16.04, util-linux 2.27.1, you can do:
dmesg --level err,warn --raw -w
where:
-wfollows the messages as they come
--levelrestricts which levels will show
--rawshows the level at the beginning of the message e.g. as<3>
answered May 22 at 12:05
Ciro Santilli 新疆改造中心 六四事件 法轮功
4,84324039
answered May 22 at 12:05
Ciro Santilli 新疆改造中心 六四事件 法轮功
4,84324039
answered May 22 at 12:05
Ciro Santilli 新疆改造中心 六四事件 法轮功
4,84324039
answered May 22 at 12:05
Ciro Santilli 新疆改造中心 六四事件 法轮功
4,84324039
4,84324039
add a comment |
add a comment |
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The items in
/procare device pointers and setters. They are not files. Welcome!!!– eyoung100
Oct 9 '14 at 20:46
Yes, of course, I will change the text, but you got what I meant :)
– Lilás
Oct 9 '14 at 20:56