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

Valdis.Kletnieks
2007-01-09T22:57:51Z

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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.

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