loglevel 7 (debug) and pr_debug()

[Denis Pithon]

Martin,

Are you sure that /var/log/messages trap DEBUG messages ? (see
/etc/rsylog.conf or something, it depends on your linux distro)
Default on Fedora is to skip debug messages. But your log output is in the
ring buffer (you can check it widt command dmesg)

I guess that your problem is not a problem but a syslog feature :)

http://www.rsyslog.com/doc/rsyslog_conf_filter.html



On Wed, Apr 16, 2014 at 1:57 PM, Martin Kepplinger <martink at posteo.de>wrote:

> 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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