Re: [PATCH 1/1] driver-core: Shut up dev_dbg_reatelimited() withoutDEBUG

[Hiroshi Doyu]

Hi Antti,

Antti Palosaari <crope@xxxxxx> wrote @ Sat, 18 Aug 2012 02:11:56 +0200:

> On 08/17/2012 09:04 AM, Hiroshi Doyu wrote:
> > dev_dbg_reatelimited() without DEBUG printed "217078 callbacks
> > suppressed". This shouldn't print anything without DEBUG.
> >
> > Signed-off-by: Hiroshi Doyu <hdoyu@xxxxxxxxxx>
> > Reported-by: Antti Palosaari <crope@xxxxxx>
> > ---
> >   include/linux/device.h |    6 +++++-
> >   1 files changed, 5 insertions(+), 1 deletions(-)
> >
> > diff --git a/include/linux/device.h b/include/linux/device.h
> > index eb945e1..d4dc26e 100644
> > --- a/include/linux/device.h
> > +++ b/include/linux/device.h
> > @@ -962,9 +962,13 @@ do {									\
> >   	dev_level_ratelimited(dev_notice, dev, fmt, ##__VA_ARGS__)
> >   #define dev_info_ratelimited(dev, fmt, ...)				\
> >   	dev_level_ratelimited(dev_info, dev, fmt, ##__VA_ARGS__)
> > +#if defined(DEBUG)
> >   #define dev_dbg_ratelimited(dev, fmt, ...)				\
> >   	dev_level_ratelimited(dev_dbg, dev, fmt, ##__VA_ARGS__)
> > -
> > +#else
> > +#define dev_dbg_ratelimited(dev, fmt, ...)			\
> > +	no_printk(KERN_DEBUG pr_fmt(fmt), ##__VA_ARGS__)
> > +#endif
> >   /*
> >    * Stupid hackaround for existing uses of non-printk uses dev_info
> >    *
> >
>
> NACK. I don't think that's correct behavior. After that patch it kills
> all output of dev_dbg_ratelimited(). If I use dynamic debugs and order
> debugs, I expect to see debugs as earlier.

You are right. I attached the update patch, just moving *_ratelimited
functions after dev_dbg() definitions.

With DEBUG defined/undefined in your "test.ko", it works fine. With
CONFIG_DYNAMIC_DEBUG, it works with "+p", but with "-p", still
"..callbacks suppressed" is printed.

$ insmod test.ko
$ echo -n 'module test +p' > /sys/kernel/debug/dynamic_debug/control"
$ rmmod test
$ dmesg | tail -15
<7>[   69.047192] (NULL device *): print_dev_dbg_ratelimited: dev_dbg_ratelimited()
<7>[   69.047233] (NULL device *): print_dev_dbg_ratelimited: dev_dbg_ratelimited()
<7>[   69.047275] (NULL device *): print_dev_dbg_ratelimited: dev_dbg_ratelimited()
<4>[   75.057045] print_dev_dbg_ratelimited: 90 callbacks suppressed
<7>[   75.063595] (NULL device *): print_dev_dbg_ratelimited: dev_dbg_ratelimited()
<7>[   75.063796] (NULL device *): print_dev_dbg_ratelimited: dev_dbg_ratelimited()
<7>[   75.063970] (NULL device *): print_dev_dbg_ratelimited: dev_dbg_ratelimited()
<7>[   75.064137] (NULL device *): print_dev_dbg_ratelimited: dev_dbg_ratelimited()
<7>[   75.064307] (NULL device *): print_dev_dbg_ratelimited: dev_dbg_ratelimited()
<7>[   75.064472] (NULL device *): print_dev_dbg_ratelimited: dev_dbg_ratelimited()
<7>[   75.064640] (NULL device *): print_dev_dbg_ratelimited: dev_dbg_ratelimited()
<7>[   75.064806] (NULL device *): print_dev_dbg_ratelimited: dev_dbg_ratelimited()
<7>[   75.064972] (NULL device *): print_dev_dbg_ratelimited: dev_dbg_ratelimited()
<7>[   75.065137] (NULL device *): print_dev_dbg_ratelimited: dev_dbg_ratelimited()
<6>[   75.065510] test module unloaded!

$ insmod test.ko
$ echo -n 'module test -p' > /sys/kernel/debug/dynamic_debug/control"
$ rmmod test
$ dmesg
...
<6>[   82.715925] test module loaded!
<6>[   82.795642] dynamic_debug:ddebug_exec_queries: processed 1 queries, with 1 matches, 0 errs
<4>[   88.892096] print_dev_dbg_ratelimited: 90 callbacks suppressed
<6>[   88.898397] test module unloaded!

Any suggestion to control "... callbacks suppressed" with
CONFIG_DYNAMIC_DEBUG would be appreciated.