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* slub: Add check for kfree() of non slab objects.
@ 2008-05-28 17:32 Christoph Lameter
  2008-05-28 19:40 ` Pekka Enberg
  0 siblings, 1 reply; 2+ messages in thread
From: Christoph Lameter @ 2008-05-28 17:32 UTC (permalink / raw)
  To: Pekka J Enberg; +Cc: mpm, linux-mm

We can detect kfree()s on non slab objects by checking for PageCompound().
Works in the same way as for ksize. This helped me catch an invalid 
kfree().

Signed-off-by: Christoph Lameter <clameter@sgi.com>

Index: linux-2.6/mm/slub.c
===================================================================
--- linux-2.6.orig/mm/slub.c	2008-05-27 21:28:55.000000000 -0700
+++ linux-2.6/mm/slub.c	2008-05-28 00:04:14.000000000 -0700
@@ -2765,6 +2765,7 @@
 
 	page = virt_to_head_page(x);
 	if (unlikely(!PageSlab(page))) {
+		BUG_ON(!PageCompound(page));
 		put_page(page);
 		return;
 	}

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^ permalink raw reply	[flat|nested] 2+ messages in thread

* Re: slub: Add check for kfree() of non slab objects.
  2008-05-28 17:32 slub: Add check for kfree() of non slab objects Christoph Lameter
@ 2008-05-28 19:40 ` Pekka Enberg
  0 siblings, 0 replies; 2+ messages in thread
From: Pekka Enberg @ 2008-05-28 19:40 UTC (permalink / raw)
  To: Christoph Lameter; +Cc: mpm, linux-mm

Christoph Lameter wrote:
> We can detect kfree()s on non slab objects by checking for PageCompound().
> Works in the same way as for ksize. This helped me catch an invalid 
> kfree().
> 
> Signed-off-by: Christoph Lameter <clameter@sgi.com>
> 
> Index: linux-2.6/mm/slub.c
> ===================================================================
> --- linux-2.6.orig/mm/slub.c	2008-05-27 21:28:55.000000000 -0700
> +++ linux-2.6/mm/slub.c	2008-05-28 00:04:14.000000000 -0700
> @@ -2765,6 +2765,7 @@
>  
>  	page = virt_to_head_page(x);
>  	if (unlikely(!PageSlab(page))) {
> +		BUG_ON(!PageCompound(page));
>  		put_page(page);
>  		return;
>  	}

Applied, thanks!

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^ permalink raw reply	[flat|nested] 2+ messages in thread

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