On Wed 25-01-17 12:15:59, Vlastimil Babka wrote:

On 01/24/2017 04:00 PM, Michal Hocko wrote:

quoted

quoted

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Well, I am not opposed to kvmalloc_array but I would argue that this
conversion cannot introduce new overflow issues. The code would have
to be broken already because even though kmalloc_array checks for the
overflow but vmalloc fallback doesn't...

Yeah I agree, but if some of the places were really wrong, after the
conversion we won't see them anymore.

quoted

If there is a general interest for this API I can add it.

I think it would be better, yes.

OK, fair enough. I will fold the following into the original patch. I
was little bit reluctant to create kvcalloc so I've made the original
callers more talkative and added | __GFP_ZERO.

Fair enough,

quoted

To be honest I do not
really like how kcalloc...

how kcalloc what?

how kcalloc hides the GFP_ZERO and the name doesn't reflect that.
 

[...]

quoted

diff --git a/net/netfilter/x_tables.c b/net/netfilter/x_tables.c
index cdc55d5ee4ad..eca16612b1ae 100644
--- a/net/netfilter/x_tables.c
+++ b/net/netfilter/x_tables.c

@@ -712,10 +712,7 @@ EXPORT_SYMBOL(xt_check_entry_offsets);
  */
 unsigned int *xt_alloc_entry_offsets(unsigned int size)
 {
-	if (size < (SIZE_MAX / sizeof(unsigned int)))
-		return kvzalloc(size * sizeof(unsigned int), GFP_KERNEL);
-
-	return NULL;
+	return kvmalloc_array(size * sizeof(unsigned int), GFP_KERNEL | __GFP_ZERO);

This one wouldn't compile.

fixed, thanks!

-- 
Michal Hocko
SUSE Labs

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