Re: [PATCH] include/linux/slab.h: new KFREE() macro.

[Valdis . Kletnieks]

On Tue, 09 Jan 2007 11:02:35 PST, Amit Choudhary said:
> Correct. And doing kfree(x); x=NULL; is not hiding that. These issues can still be debugged by
> using the slab debugging options. One other benefit of doing this is that if someone tries to
> access the same memory again using the variable 'x', then he will get an immediate crash. And the
> problem can be solved immediately, without using the slab debugging options. I do not yet
> understand how doing this hides the bugs, obfuscates the code, etc. because I haven't seen an
> example yet, but only blanket statements.

char *broken() {
	char *x, *y;
	x = kmalloc(100);
	y = x;
	kfree(x);
	x = NULL;
	return y;
}

Setting x to NULL doesn't do anything to fix the *real* bug here, because
the problematic reference is held in y, not x.  So you never get a crash
because somebody dereferences x.

Attachment: pgp00000.pgp
Description: PGP signature