loglevel 7 (debug) and pr_debug()

[martink@posteo.de (Martin Kepplinger)]

Am 2014-04-16 11:00, schrieb Arun KS:
> Hi Martin,
> 
> On Wed, Apr 16, 2014 at 2:13 PM, Martin Kepplinger <martink@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/*

> 
> 
> Thanks,
> Arun
>>
>> thanks!
>>                      martin
>>
>> --
>> Martin Kepplinger
>> e-mail        martink AT posteo DOT at
>> chat (XMPP)   martink AT jabber DOT at
>>
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