[PATCH][2/2] fix unchecked returns from kmalloc() (in mm/slab.c)

[Jesper Juhl]

Problem reported by Katrina Tsipenyuk and the Fortify Software engineering
team in thread with subject "PROBLEM: unchecked returns from kmalloc() in
linux-2.6.10-rc2".

Unfortunately I'm not very familliar with the code in question, and since 
I didn't find a really good way to deal with a failing kmalloc() here I 
settled for second best which is to add a BUG_ON() in case kmalloc fails. 
This will at least crash in a sane way at the point the problem occoures 
rather than getting strange problems at a (possibly) later time. If 
someone who's familliar with how this code works has a better solution 
then please step forward :) but in the mean time I think this is at least 
a slight improvement over the current situation.

Patch has been compile tested and boot tested and didn't blow up 
instantly, but please review before applying.


Signed-off-by: Jesper Juhl <juhl-lkml@xxxxxx>

diff -up linux-2.6.10-rc3-bk2-orig/mm/slab.c linux-2.6.10-rc3-bk2/mm/slab.c
--- linux-2.6.10-rc3-bk2-orig/mm/slab.c	2004-12-06 22:24:56.000000000 +0100
+++ linux-2.6.10-rc3-bk2/mm/slab.c	2004-12-07 21:27:20.000000000 +0100
@@ -804,6 +804,7 @@ void __init kmem_cache_init(void)
 		void * ptr;
 		
 		ptr = kmalloc(sizeof(struct arraycache_init), GFP_KERNEL);
+		BUG_ON(ptr == NULL);	/* FIXME: Can a failed kmalloc be handled better? */
 		local_irq_disable();
 		BUG_ON(ac_data(&cache_cache) != &initarray_cache.cache);
 		memcpy(ptr, ac_data(&cache_cache), sizeof(struct arraycache_init));
@@ -811,6 +812,7 @@ void __init kmem_cache_init(void)
 		local_irq_enable();
 	
 		ptr = kmalloc(sizeof(struct arraycache_init), GFP_KERNEL);
+		BUG_ON(ptr == NULL);	/* FIXME: Can a failed kmalloc be handled better? */
 		local_irq_disable();
 		BUG_ON(ac_data(malloc_sizes[0].cs_cachep) != &initarray_generic.cache);
 		memcpy(ptr, ac_data(malloc_sizes[0].cs_cachep),



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