Re: [PATCH v3 03/14] mm, hugetlb: protect region tracking via newlyintroduced resv_map lock

[Davidlohr Bueso]

On Wed, 2013-12-18 at 15:53 +0900, Joonsoo Kim wrote:
> There is a race condition if we map a same file on different processes.
> Region tracking is protected by mmap_sem and hugetlb_instantiation_mutex.
> When we do mmap, we don't grab a hugetlb_instantiation_mutex, but,
> grab a mmap_sem. This doesn't prevent other process to modify region
> structure, so it can be modified by two processes concurrently.
> 
> To solve this, I introduce a lock to resv_map and make region manipulation
> function grab a lock before they do actual work. This makes region
> tracking safe.
> 
> Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>

Reviewed-by: Davidlohr Bueso <davidlohr@xxxxxx>

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