linux-kernel - Re: [PATCH v4] mm: hwposion: support recovery from ksm_might_need_to

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Message-ID: <20230207223835.GA1039769@u2004>
Date:   Wed, 8 Feb 2023 07:38:35 +0900
From:   Naoya Horiguchi <naoya.horiguchi@...ux.dev>
To:     Kefeng Wang <wangkefeng.wang@...wei.com>
Cc:     akpm@...ux-foundation.org, naoya.horiguchi@....com,
        linux-mm@...ck.org, linmiaohe@...wei.com, tony.luck@...el.com,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v4] mm: hwposion: support recovery from
 ksm_might_need_to_copy()

On Wed, Feb 01, 2023 at 03:44:33PM +0800, Kefeng Wang wrote:
> When the kernel copy a page from ksm_might_need_to_copy(), but runs
> into an uncorrectable error, it will crash since poisoned page is
> consumed by kernel, this is similar to the issue recently fixed by
> Copy-on-write poison recovery.
> 
> When an error is detected during the page copy, return VM_FAULT_HWPOISON
> in do_swap_page(), and install a hwpoison entry in unuse_pte() when
> swapoff, which help us to avoid system crash. Note, memory failure on
> a KSM page will be skipped, but still call memory_failure_queue() to
> be consistent with general memory failure process, and we could support
> KSM page recovery in the feature.
> 
> Signed-off-by: Kefeng Wang <wangkefeng.wang@...wei.com>

Looks good to me, thank you.

Reviewed-by: Naoya Horiguchi <naoya.horiguchi@....com>