Re: [PATCH 2/2] Use the cut_here() function in AFS, CacheFiles, FS-Cache and RxRPC

[Linus Torvalds <torvalds@linux-foundation.org>]

On Thu, 20 Aug 2009, David Howells wrote:
>
> Use the cut_here() function in AFS, CacheFiles, FS-Cache and RxRPC to put
> pertinent extra information between the "cut here" line and the BUG report.

No. This is fundamentally the wrong approach.

>  #define ASSERT(X)						\
>  do {								\
> 	if (unlikely(!(X))) {					\
> -		printk(KERN_ERR "\n");				\
> +		cut_here();					\
>  		printk(KERN_ERR "AFS: Assertion failed\n");	\
>  		BUG();						\

Instead of doing that "cut_here()" thing, you should either use the WARN() 
thing that has a format string already, or we should extend BUG() to have 
that kind of thing too. So in this case I think that you should use WARN() 
instead, ie change it to be

	#define ASSERT(x) do {						\
		if (WARN(X, "AFS: Assertion failed"))		\
			do_exit(SIGSEGV);				\
	} while (0)

instead. And yes, in the long run, I really think we should just extend 
the current BUG() reporting to have that kind of semantics, but I think 
your "cut_here()" thing is a horrible hack.

		Linus