[KJ] is there a kernel standard for assertions?

[KJ] is there a kernel standard for assertions?

[Robert P. J. Day]

  it seems like lots of kernel code is re-inventing the idea of an
assertion.  is there no single basic standard for assertions in the
kernel?

rday

-- 
====================================
Robert P. J. Day
Linux Consulting, Training and Annoying Kernel Pedantry
Waterloo, Ontario, CANADA

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Re: [KJ] is there a kernel standard for assertions?

[Matthew Wilcox]

On Sat, Mar 17, 2007 at 03:51:49PM -0400, Robert P. J. Day wrote:
>   it seems like lots of kernel code is re-inventing the idea of an
> assertion.  is there no single basic standard for assertions in the
> kernel?

BUG_ON().
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Re: [KJ] is there a kernel standard for assertions?

[Adrian Bunk]

On Sat, Mar 17, 2007 at 02:39:25PM -0600, Matthew Wilcox wrote:
> On Sat, Mar 17, 2007 at 03:51:49PM -0400, Robert P. J. Day wrote:
> >   it seems like lots of kernel code is re-inventing the idea of an
> > assertion.  is there no single basic standard for assertions in the
> > kernel?
> 
> BUG_ON().

Or WARN_ON() if it's considered non-fatal.

cu
Adrian

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Re: [KJ] is there a kernel standard for assertions?

[Robert P. J. Day]

On Sat, 17 Mar 2007, Adrian Bunk wrote:

> On Sat, Mar 17, 2007 at 02:39:25PM -0600, Matthew Wilcox wrote:
> > On Sat, Mar 17, 2007 at 03:51:49PM -0400, Robert P. J. Day wrote:
> > >   it seems like lots of kernel code is re-inventing the idea of an
> > > assertion.  is there no single basic standard for assertions in the
> > > kernel?
> >
> > BUG_ON().
>
> Or WARN_ON() if it's considered non-fatal.

i'm aware of both of those macros, which is why i'm wondering why so
many developers insist on inventing their own version of an "assert"
routine.  given all of the *existing* debugging routines, shouldn't
inventing your own be discouraged?  is that something that could be
turned into a KJ project of some kind?

rday
-- 
====================================
Robert P. J. Day
Linux Consulting, Training and Annoying Kernel Pedantry
Waterloo, Ontario, CANADA

http://fsdev.net/wiki/index.php?title=Main_Page
====================================
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Re: [KJ] is there a kernel standard for assertions?

[Arnd Bergmann]

On Saturday 17 March 2007 22:46:39 Robert P. J. Day wrote:
> i'm aware of both of those macros, which is why i'm wondering why so
> many developers insist on inventing their own version of an "assert"
> routine.  given all of the *existing* debugging routines, shouldn't
> inventing your own be discouraged?  is that something that could be
> turned into a KJ project of some kind?

Yes. I guess most of the assert() implementations in the kernel are
older than BUG_ON() and WARN_ON(). Adding new ones is normally
discouraged.

	Arnd <><

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Re: [KJ] is there a kernel standard for assertions?

[Richard Knutsson]

Robert P. J. Day wrote:
> On Sat, 17 Mar 2007, Adrian Bunk wrote:
>
>   
>> On Sat, Mar 17, 2007 at 02:39:25PM -0600, Matthew Wilcox wrote:
>>     
>>> On Sat, Mar 17, 2007 at 03:51:49PM -0400, Robert P. J. Day wrote:
>>>       
>>>>   it seems like lots of kernel code is re-inventing the idea of an
>>>> assertion.  is there no single basic standard for assertions in the
>>>> kernel?
>>>>         
>>> BUG_ON().
>>>       
>> Or WARN_ON() if it's considered non-fatal.
>>     
>
> i'm aware of both of those macros, which is why i'm wondering why so
> many developers insist on inventing their own version of an "assert"
> routine.  given all of the *existing* debugging routines, shouldn't
> inventing your own be discouraged?  is that something that could be
> turned into a KJ project of some kind?
>   
Is there any way to just enable the debugging for one sub-system and not 
the whole tree?

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Re: [KJ] is there a kernel standard for assertions?

[Randy Dunlap]

On Sun, 18 Mar 2007 04:39:39 +0100 Richard Knutsson wrote:

> Robert P. J. Day wrote:
> > On Sat, 17 Mar 2007, Adrian Bunk wrote:
> >
> >   
> >> On Sat, Mar 17, 2007 at 02:39:25PM -0600, Matthew Wilcox wrote:
> >>     
> >>> On Sat, Mar 17, 2007 at 03:51:49PM -0400, Robert P. J. Day wrote:
> >>>       
> >>>>   it seems like lots of kernel code is re-inventing the idea of an
> >>>> assertion.  is there no single basic standard for assertions in the
> >>>> kernel?
> >>>>         
> >>> BUG_ON().
> >>>       
> >> Or WARN_ON() if it's considered non-fatal.
> >>     
> >
> > i'm aware of both of those macros, which is why i'm wondering why so
> > many developers insist on inventing their own version of an "assert"
> > routine.  given all of the *existing* debugging routines, shouldn't
> > inventing your own be discouraged?  is that something that could be
> > turned into a KJ project of some kind?
> >   
> Is there any way to just enable the debugging for one sub-system and not 
> the whole tree?

A few subsystems have specific debug-enabling config symbols,
like USB and ACPI and KOBJECT and PM (Power Management) and PCI,
PCMCIA, NETFILTER, IRDA, IEEE80211, DRIVERS, MTD, PNP, SCSI,
SPI, SOUND, HID, MMC, EDAC, JBD, JFS, NTFS, UFS, CIFS, DLM,
and KOBJECTS (just to name some of the big ones).

But BUG_ON() and WARN_ON() are often used without the aid (i.e.,
enabling) of those DEBUG config symbols.

---
~Randy
*** Remember to use Documentation/SubmitChecklist when testing your code ***
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Re: [KJ] is there a kernel standard for assertions?

[Richard Knutsson]

Randy Dunlap wrote:
> On Sun, 18 Mar 2007 04:39:39 +0100 Richard Knutsson wrote:
>
>   
>> Robert P. J. Day wrote:
>>     
>>> On Sat, 17 Mar 2007, Adrian Bunk wrote:
>>>
>>>   
>>>       
>>>> On Sat, Mar 17, 2007 at 02:39:25PM -0600, Matthew Wilcox wrote:
>>>>     
>>>>         
>>>>> On Sat, Mar 17, 2007 at 03:51:49PM -0400, Robert P. J. Day wrote:
>>>>>       
>>>>>           
>>>>>>   it seems like lots of kernel code is re-inventing the idea of an
>>>>>> assertion.  is there no single basic standard for assertions in the
>>>>>> kernel?
>>>>>>         
>>>>>>             
>>>>> BUG_ON().
>>>>>       
>>>>>           
>>>> Or WARN_ON() if it's considered non-fatal.
>>>>     
>>>>         
>>> i'm aware of both of those macros, which is why i'm wondering why so
>>> many developers insist on inventing their own version of an "assert"
>>> routine.  given all of the *existing* debugging routines, shouldn't
>>> inventing your own be discouraged?  is that something that could be
>>> turned into a KJ project of some kind?
>>>   
>>>       
>> Is there any way to just enable the debugging for one sub-system and not 
>> the whole tree?
>>     
>
> A few subsystems have specific debug-enabling config symbols,
> like USB and ACPI and KOBJECT and PM (Power Management) and PCI,
> PCMCIA, NETFILTER, IRDA, IEEE80211, DRIVERS, MTD, PNP, SCSI,
> SPI, SOUND, HID, MMC, EDAC, JBD, JFS, NTFS, UFS, CIFS, DLM,
> and KOBJECTS (just to name some of the big ones).
>
> But BUG_ON() and WARN_ON() are often used without the aid (i.e.,
> enabling) of those DEBUG config symbols.
>   
"Often used without"? Is it possible to enable BUG_ON() and WARN_ON() 
with those config symbols? I can see how to disable ex BUG_ON by:
<in header>

#ifndef DEBUG_CONFIG_SYMBOL

#undef BUG_ON

#define BUG_ON(x)    do {} while(0);

#endif

or

<in code>

#ifdef DEBUG_CONFIG_SYMBOL
	BUG_ON(...)
#endif


But how to enable them when DEBUG is not defined? Otherwise I can 
understand if maintainers do not want to use BUG_ON/WARN_ON and get the 
debugging-info from the whole system.
Would something like SUBSYS_BUG_ON() be acceptable, who are just like 
BUG_ON() but is (en/dis)abled by the subsystems debug-config-symbol? 
(Would require some SUBSYS_BUG_ON_INIT() to define the debug-symbol)

Just my 2c
Richard Knutsson

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