Re: [PATCH 5/9] treewide: use kv[mz]alloc* rather than opencoded variants

On Mon, Jan 30, 2017 at 1:49 AM, Michal Hocko [off-list ref] wrote:

From: Michal Hocko <mhocko@suse.com>

There are many code paths opencoding kvmalloc. Let's use the helper
instead. The main difference to kvmalloc is that those users are usually
not considering all the aspects of the memory allocator. E.g. allocation
requests <= 32kB (with 4kB pages) are basically never failing and invoke
OOM killer to satisfy the allocation. This sounds too disruptive for
something that has a reasonable fallback - the vmalloc. On the other
hand those requests might fallback to vmalloc even when the memory
allocator would succeed after several more reclaim/compaction attempts
previously. There is no guarantee something like that happens though.

This patch converts many of those places to kv[mz]alloc* helpers because
they are more conservative.

Changes since v1
- add kvmalloc_array - this might silently fix some overflow issues
  because most users simply didn't check the overflow for the vmalloc
  fallback.

Awesome, thanks for adding that API. :)

Acked-by: Kees Cook <redacted>

-Kees

-- 
Kees Cook
Nexus Security

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