Re: [PATCH 2/5] HWPOISON: fix tasklist_lock/anon_vma locking order

[Rik van Riel]

Wu Fengguang wrote:
> To avoid possible deadlock. Proposed by Nick Piggin:
>
>   You have tasklist_lock(R) nesting outside i_mmap_lock, and inside anon_vma
>   lock. And anon_vma lock nests inside i_mmap_lock.
>
>   This seems fragile. If rwlocks ever become FIFO or tasklist_lock changes
>   type (maybe -rt kernels do it), then you could have a task holding
>   anon_vma lock and waiting for tasklist_lock, and another holding tasklist
>   lock and waiting for i_mmap_lock, and another holding i_mmap_lock and
>   waiting for anon_vma lock.
>
> CC: Nick Piggin <npiggin@xxxxxxx>
> Signed-off-by: Wu Fengguang <fengguang.wu@xxxxxxxxx>

Acked-by: Rik van Riel <riel@xxxxxxxxxx>

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