Re: [PATCH] mm: replace vma_lock_anon_vma with anon_vma_lock_read/write

[Kirill A. Shutemov]

On Tue, Feb 02, 2016 at 12:10:19PM +0300, Konstantin Khlebnikov wrote:
> Sequence vma_lock_anon_vma() - vma_unlock_anon_vma() isn't safe if
> anon_vma appeared between lock and unlock. We have to check anon_vma
> first or call anon_vma_prepare() to be sure that it's here. There are
> only few users of these legacy helpers. Let's get rid of them.
> 
> This patch fixes anon_vma lock imbalance in validate_mm().
> Write lock isn't required here, read lock is enough.
> 
> And reorders expand_downwards/expand_upwards: security_mmap_addr() and
> wrapping-around check don't have to be under anon vma lock.
> 
> Signed-off-by: Konstantin Khlebnikov <koct9i@xxxxxxxxx>
> Reported-by: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
> Link: https://lkml.kernel.org/r/CACT4Y+Y908EjM2z=706dv4rV6dWtxTLK9nFg9_7DhRMLppBo2g@xxxxxxxxxxxxxx

Acked-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>

-- 
 Kirill A. Shutemov