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Subject: Re: [PATCH v2 1/2] mm: soft-offline: return -EBUSY if
 set_hwpoison_free_buddy_page() fails
To:     Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>, linux-mm@kvack.org
Cc:     Andrew Morton <akpm@linux-foundation.org>,
        Michal Hocko <mhocko@kernel.org>,
        xishi.qiuxishi@alibaba-inc.com,
        "Chen, Jerry T" <jerry.t.chen@intel.com>,
        "Zhuo, Qiuxu" <qiuxu.zhuo@intel.com>, linux-kernel@vger.kernel.org
References: <1560154686-18497-1-git-send-email-n-horiguchi@ah.jp.nec.com>
 <1560154686-18497-2-git-send-email-n-horiguchi@ah.jp.nec.com>
From:   Mike Kravetz <mike.kravetz@oracle.com>
Message-ID: <8e8e6afc-cddb-9e79-c8ae-c2814b73cbe9@oracle.com>
Date:   Mon, 10 Jun 2019 17:19:45 -0700
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On 6/10/19 1:18 AM, Naoya Horiguchi wrote:
> The pass/fail of soft offline should be judged by checking whether the
> raw error page was finally contained or not (i.e. the result of
> set_hwpoison_free_buddy_page()), but current code do not work like that.
> So this patch is suggesting to fix it.
> 
> Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
> Fixes: 6bc9b56433b76 ("mm: fix race on soft-offlining")
> Cc: <stable@vger.kernel.org> # v4.19+

Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>

To follow-up on Andrew's comment/question about user visible effects.  Without
this fix, there are cases where madvise(MADV_SOFT_OFFLINE) may not offline the
original page and will not return an error.  Are there any other visible
effects?

-- 
Mike Kravetz