Re: [RFC][PATCH] hugetlb: fix resv_map leak in error path

From: KOSAKI Motohiro
Date: Mon May 21 2012 - 14:23:54 EST


On 5/18/2012 2:46 PM, Dave Hansen wrote:
> When called for anonymous (non-shared) mappings,
> hugetlb_reserve_pages() does a resv_map_alloc(). It depends on
> code in hugetlbfs's vm_ops->close() to release that allocation.
>
> However, in the mmap() failure path, we do a plain unmap_region()
> without the remove_vma() which actually calls vm_ops->close().
>
> This is a decent fix. This leak could get reintroduced if
> new code (say, after hugetlb_reserve_pages() in
> hugetlbfs_file_mmap()) decides to return an error. But, I think
> it would have to unroll the reservation anyway.
>
> This hasn't been extensively tested. Pretty much compile and
> boot tested along with Christoph's test case.
>
> Comments?
>
>
> Signed-off-by: Dave Hansen <dave@xxxxxxxxxxxxxxxxxx>
> ---

I don't think this is cleaner fix. but I also think we should fix the leak
asap. so Let's simple fix first.

Acked-by: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx>

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