about pr_debug

about pr_debug

[lx]

hi all:
       I'm confused with pr_debug. My codes is:
###########################################
#include <linux/module.h>
#include <linux/kernel.h>

static int __init init_page_dir(void)
{
    pr_debug("Hello world\n");
    return 0;
}

static void __exit exit_page_dir(void)
{
    pr_debug("\nGoodbye now...\n\n");
}

MODULE_LICENSE("GPL");
module_init(init_page_dir);
module_exit(exit_page_dir);
###########################################
I make it, and insmod it. But the messages of "Hello world" don't show.

So, My question is If i want to fix it , I should set the
*DEFAULT_MESSAGE_LOGLEVEL
and *
*rebuild the kernel ?*

My kernel version is:2.6.18
OS is: centOS

Thank you.
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about pr_debug

[Real Name]

On Wed, Jun 25, 2014 at 02:09:40PM +0800, lx wrote:
> hi all:
>        I'm confused with pr_debug. My codes is:
> ###########################################
> #include <linux/module.h>
> #include <linux/kernel.h>
> 
> static int __init init_page_dir(void)
> {
>     pr_debug("Hello world\n");
>     return 0;
> }
> 
> static void __exit exit_page_dir(void)
> {
>     pr_debug("\nGoodbye now...\n\n");
> }
> 
> MODULE_LICENSE("GPL");
> module_init(init_page_dir);
> module_exit(exit_page_dir);
> ###########################################
> I make it, and insmod it. But the messages of "Hello world" don't show.
> 
> So, My question is If i want to fix it , I should set the
> *DEFAULT_MESSAGE_LOGLEVEL
> and *
> *rebuild the kernel ?*
>

https://www.kernel.org/doc/local/pr_debug.txt

> My kernel version is:2.6.18
> OS is: centOS
> 
> Thank you.

> _______________________________________________
> Kernelnewbies mailing list
> Kernelnewbies at kernelnewbies.org
> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies

about pr_debug

[Varka Bhadram]

refer this :https://www.kernel.org/doc/local/pr_debug.txt

On 06/25/2014 11:39 AM, lx wrote:
> hi all:
>        I'm confused with pr_debug. My codes is:
> ###########################################
> #include <linux/module.h>
> #include <linux/kernel.h>
>
> static int __init init_page_dir(void)
> {
>     pr_debug("Hello world\n");
>     return 0;
> }
>
> static void __exit exit_page_dir(void)
> {
>     pr_debug("\nGoodbye now...\n\n");
> }
>
> MODULE_LICENSE("GPL");
> module_init(init_page_dir);
> module_exit(exit_page_dir);
> ###########################################
> I make it, and insmod it. But the messages of "Hello world" don't show.
>
> So, My question is If i want to fix it , I should set the 
> /DEFAULT_MESSAGE_LOGLEVEL and /
> /rebuild the kernel ?/
>
> My kernel version is:2.6.18
> OS is: centOS
>
> Thank you.
>
>
> _______________________________________________
> Kernelnewbies mailing list
> Kernelnewbies at kernelnewbies.org
> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies

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about pr_debug

[Bjørn Mork]

Varka Bhadram <varkabhadram@gmail.com> writes:

> refer this :https://www.kernel.org/doc/local/pr_debug.txt

That seems a little outdated since it doesn't mention the extremely
useful dynamic debug feature.  So please read
https://www.kernel.org/doc/Documentation/dynamic-debug-howto.txt
as well.

The ability to dynamically switch on and off debug messages per callsite
is extremely useful.  And it also enables you to switch on some extra
info you often want, like function names, without having to explictly
put them into every format string.

I recommend setting CONFIG_DYNAMIC_DEBUG and taking a look at
/sys/kernel/debug/dynamic_debug/control if you ever do any kernel
development.



Bj?rn

about pr_debug

[lx]

thank you.
But the Makefile is so simple and Not use "cc".
#################################
obj-m   := task_01.o

KDIR:=/lib/modules/`uname -r`/build
PWD:=$(shell pwd)

default:
    echo $KDIR
    $(MAKE) -C $(KDIR) M=$(PWD) modules
#################################

So, how to add "CFLAGS"?


2014-06-25 16:20 GMT+08:00 Bj?rn Mork <bjorn@mork.no>:

> Varka Bhadram <varkabhadram@gmail.com> writes:
>
> > refer this :https://www.kernel.org/doc/local/pr_debug.txt
>
> That seems a little outdated since it doesn't mention the extremely
> useful dynamic debug feature.  So please read
> https://www.kernel.org/doc/Documentation/dynamic-debug-howto.txt
> as well.
>
> The ability to dynamically switch on and off debug messages per callsite
> is extremely useful.  And it also enables you to switch on some extra
> info you often want, like function names, without having to explictly
> put them into every format string.
>
> I recommend setting CONFIG_DYNAMIC_DEBUG and taking a look at
> /sys/kernel/debug/dynamic_debug/control if you ever do any kernel
> development.
>
>
>
> Bj?rn
>
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about pr_debug

[Varka Bhadram]

On 06/25/2014 03:17 PM, lx wrote:
> thank you.
> But the Makefile is so simple and Not use "cc".
> #################################
> obj-m   := task_01.o
>
  CFLAGS_task_01.o := -DDEBUG

> KDIR:=/lib/modules/`uname -r`/build
> PWD:=$(shell pwd)
>
> default:
>     echo $KDIR
>     $(MAKE) -C $(KDIR) M=$(PWD) modules
> #################################
>
> So, how to add "CFLAGS"?
>
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about pr_debug

[lx]

Thank you. I fix it

EXTRA_CFLAGS += -DDEBUG


2014-06-25 17:50 GMT+08:00 Varka Bhadram <varkabhadram@gmail.com>:

>  On 06/25/2014 03:17 PM, lx wrote:
>
> thank you.
> But the Makefile is so simple and Not use "cc".
> #################################
>  obj-m   := task_01.o
>
>    CFLAGS_task_01.o := -DDEBUG
>
>   KDIR:=/lib/modules/`uname -r`/build
> PWD:=$(shell pwd)
>
>  default:
>     echo $KDIR
>     $(MAKE) -C $(KDIR) M=$(PWD) modules
>  #################################
>
>  So, how to add "CFLAGS"?
>
>
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about pr_debug

[anish singh]

On Tue, Jun 24, 2014 at 11:09 PM, lx <lxlenovostar@gmail.com> wrote:

> hi all:
>        I'm confused with pr_debug. My codes is:
> ###########################################
> #include <linux/module.h>
> #include <linux/kernel.h>
>
> static int __init init_page_dir(void)
> {
>     pr_debug("Hello world\n");
>
use printk or do echo "file_name +p" >
/sys/kernel/debug/dyanmic_debug/control

>     return 0;
> }
>
> static void __exit exit_page_dir(void)
> {
>     pr_debug("\nGoodbye now...\n\n");
> }
>
> MODULE_LICENSE("GPL");
> module_init(init_page_dir);
> module_exit(exit_page_dir);
> ###########################################
> I make it, and insmod it. But the messages of "Hello world" don't show.
>
> So, My question is If i want to fix it , I should set the *DEFAULT_MESSAGE_LOGLEVEL
> and *
> *rebuild the kernel ?*
>
> My kernel version is:2.6.18
> OS is: centOS
>
> Thank you.
>
> _______________________________________________
> Kernelnewbies mailing list
> Kernelnewbies at kernelnewbies.org
> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>
>
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about pr_debug

[Pranay Srivastava]

On Wed, Jun 25, 2014 at 11:39 AM, lx <lxlenovostar@gmail.com> wrote:
> hi all:
>        I'm confused with pr_debug. My codes is:
> ###########################################
> #include <linux/module.h>
> #include <linux/kernel.h>
>
> static int __init init_page_dir(void)
> {
>     pr_debug("Hello world\n");
>     return 0;
> }

Add ccflags-y += -DDEBUG in your Kbuild or Makefile that should work.

>
> static void __exit exit_page_dir(void)
> {
>     pr_debug("\nGoodbye now...\n\n");
> }
>
> MODULE_LICENSE("GPL");
> module_init(init_page_dir);
> module_exit(exit_page_dir);
> ###########################################
> I make it, and insmod it. But the messages of "Hello world" don't show.
>
> So, My question is If i want to fix it , I should set the
> DEFAULT_MESSAGE_LOGLEVEL and
> rebuild the kernel ?
>
> My kernel version is:2.6.18
> OS is: centOS
>
> Thank you.
>
> _______________________________________________
> Kernelnewbies mailing list
> Kernelnewbies at kernelnewbies.org
> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>



-- 
        ---P.K.S