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Date: Sat, 1 Jun 2002 14:19:02 -0300
From: Arnaldo Carvalho de Melo <acme@conectiva.com.br>
To: Andrew Morton <akpm@zip.com.au>
Cc: Linus Torvalds <torvalds@transmeta.com>,
        lkml <linux-kernel@vger.kernel.org>
Subject: Re: [patch 2/16] list_head debugging
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Em Sat, Jun 01, 2002 at 01:40:03AM -0700, Andrew Morton escreveu:
> A common and very subtle bug is to use list_heads which aren't on any
> lists.  It causes kernel memory corruption which is observed long after
> the offending code has executed.
 
> The patch nulls out the dangling pointers so we get a nice oops at the
> site of the buggy code.

> =====================================
> 
> --- 2.5.19/include/linux/list.h~list-debug	Sat Jun  1 01:18:05 2002
> +++ 2.5.19-akpm/include/linux/list.h	Sat Jun  1 01:18:05 2002
> @@ -94,6 +94,11 @@ static __inline__ void __list_del(struct
>  static __inline__ void list_del(struct list_head *entry)
>  {
>  	__list_del(entry->prev, entry->next);

#ifdef CONFIG_DEBUG_LIST_DEL_NULLIFY

> +	entry->next = 0;
> +	entry->prev = 0;

#endif

>  }

8) And get this configured in the Debug section of make *config

The kernel will always have bugs ;)

- Arnaldo
-
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