loglevel 7 (debug) and pr_debug()

[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


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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