Re: filldir[64] oddness

["David S. Miller" <davem@davemloft.net>]

From: Dave Jones <davej@redhat.com>
Date: Wed, 8 Mar 2006 23:27:44 -0500

> #define NAME_OFFSET(de) ((int) ((de)->d_name - (char __user *) (de)))
> #define ROUND_UP(x) (((x)+sizeof(long)-1) & ~(sizeof(long)-1))
> 
> 140  	static int filldir(void * __buf, const char * name, int namlen, loff_t offset,
> 141  			   ino_t ino, unsigned int d_type)
> 142  	{
> 143  		struct linux_dirent __user * dirent;
> 144  		struct getdents_callback * buf = (struct getdents_callback *) __buf
> 145  		int reclen = ROUND_UP(NAME_OFFSET(dirent) + namlen + 2);
> 
> How come that NAME_OFFSET isn't causing an oops when
> it dereferences stackjunk->d_name ?

d_name a char[] array, and we're just doing pointer arithmetic
here.  It's the same as "offsetof(d_name, struct linux_dirent)"
or something like that.

I think coverity is being trigger happy in this case :-)
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