Re: [RFC] fix slub krealloc()

From: Christoph Lameter
Date: Mon Jul 23 2007 - 16:32:19 EST


On Wed, 18 Jul 2007 17:42:11 +0200
Johannes Berg <johannes@xxxxxxxxxxxxxxxx> wrote:

> Commit ef2ad80c7d255ed0449eda947c2d700635b7e0f5 breaks
> krealloc(NULL, ...) badly, it BUG_ON()s.
>
> This patch fixes it but the fix should probably be in mm/util.c
> because the documentation says that krealloc(NULL, x, gfp) is
> equivalent to kmalloc(x, gfp) and that's not true any more even after
> this patch when you do krealloc(NULL, 0, gfp)

Right. We need to fix util.c. ksize should not be called with a NULL
parameter.
Index: linux-2.6/mm/util.c
===================================================================
--- linux-2.6.orig/mm/util.c 2007-07-23 13:29:42.000000000 -0700
+++ linux-2.6/mm/util.c 2007-07-23 13:31:28.000000000 -0700
@@ -88,7 +88,11 @@ void *krealloc(const void *p, size_t new
return ZERO_SIZE_PTR;
}

- ks = ksize(p);
+ if (p)
+ ks = ksize(p);
+ else
+ ks = 0;
+
if (ks >= new_size)
return (void *)p;

-
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