loglevel 7 (debug) and pr_debug()

[Martin Kepplinger]

Am 16.04.2014 13:43 schrieb Denis Pithon:
> Martin,
> 
> I'm not sure did you enable DDEBUG when compiling your module ?
> pr_debug() macro is discarded if you omit DEBUG in compile time
> 
> A sample Makefile which enable pr_debug() :
> 
> obj-m += my_modue.o
> 
> KDIR ?= /lib/modules/`uname -r`/build
> CFLAGS_my_module.o := -DDEBUG
> 
> all:
>  make -C $(KDIR) M=$(PWD) modules
> 
> clean:
>  make -C $(KDIR) M=$(PWD) clean
> 
> Let me know ...
> regards

Thanks,

I did not, but now added -DDEBUG. The exact line is:
CFLAGS_my_module.o := -DDEBUG
when "my_module.o" is my object file. Did I get that right?

That doesn't change anything unfortunately. I can not read pr_debug() 
unless I
explicitely activate it in /sys/kernel/debug/dynamic_debug/control 
*after* insmod.

I'd like to just read all pr_debug() messages like pr_info().

thanks for your time!

> 
> On Wed, Apr 16, 2014 at 1:11 PM, Martin Kepplinger <martink at posteo.de> 
> wrote:
> 
>> Am 16.04.2014 11:58 schrieb Arun KS:
>> 
>>> Hi Martin,
>>> 
>>> On Wed, Apr 16, 2014 at 2:46 PM, Martin Kepplinger 
>>> <martink at posteo.de>
>>> wrote:
>>>> Am 2014-04-16 11:00, schrieb Arun KS:
>>>>> Hi Martin,
>>>  >>
>>>>> On Wed, Apr 16, 2014 at 2:13 PM, Martin Kepplinger
>>>>> <martink at posteo.de> wrote:
>>>>>> I'm on Debian here and I don't really get pr_debug and
>>>>>> printk(KERN_DEBUG
>>>  >>> ...). Let's stick to pr_debug.
>>>>>> 
>>>>>> I have DYNAMIC_DEBUG enabled and
>>>>>> root at laptop:/proc/sys/kernel# cat /proc/sys/kernel/printk
>>>>>> 7       7       1       7
>>>  >> This shows the console log level.
>>>>> This file controls the traffic to console. But all the log 
>>>>> messages
>>>>> will be present in logbuf.
>>>> 
>>>> How do I view debug messages from logbuf?
>>>  >
>>>>> 
>>>>>> 
>>>>>> I write a module with pr_debug's. I load the module and I *don't*
>>>>>> see
>>>>>> anything in /var/log/messages (or anywhere in /var/log/* ). 
>>>>>> Adding
>>>>>> #define DEBUG doesn't help.
>>>  >>>
>>>>>> /sys/kernel/debug/dynamic_debug/control has the pr_debug entries 
>>>>>> I
>>>>>> use
>>>>>> in my loaded module.
>>>>>> 
>>>>>> In short: How do I see debug log messages? Using pr_info() works 
>>>>>> as
>>>  >>> expected. What am I missing? Do I need to edit my Makefile?
>>>>> Did you enable dynamic printing for your file?
>>>>> 
>>>>> Below command enables dynamic printing for file sdhci.c.
>>>>> echo 'file sdhci.c +p' > /sys/kernel/debug/dynamic_debug/control
>>>  >
>>>> well. I tried that. The thing is, the pr_debug() symbols are in
>>>> "control" only after "insmod my_module". Then I can echo -n 'file
>>>> my_mobule.c +p' > control
>>>> But my pr_debug() messages get printed directly after insmod,
>>>> basically
>>>  > in my module_init function. Enabling my file doesn't output
>>> anything in
>>>> /var/log/*
>>> So now you know why your pr_debug is absent in logbuf.
>>> 
>>> You can make your module as a built in and use bootargs.
>>> 
>>> eg:
>>> dyndbg="file your_filename.c +p"
>>> 
>>> Thanks,
>>> Arun
>>> 
>> 
>> So it's *not* possible at all to get pr_debug() messages just like
>> pr_info() messages?
>> Of what I've read, I assumed pr_debug() is just loglevel 7.
>> 
>> thanks for your help!
>> 
>>>> 
>>>>> 
>>>>> 
>>>>> Thanks,
>>>>> Arun
>>>>>> 
>>>>>> thanks!
>>>>>>                      martin
>>>  >>>
>>>>>> --
>>>>>> Martin Kepplinger
>>>>>> e-mail        martink AT posteo DOT at
>>>>>> chat (XMPP)   martink AT jabber DOT at
>>>>>> 
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