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bh=mpIpA+1gb4NUMq4biGISkWZOSJ4nEB3zKh/uw92n970=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=I6btUPV5HS9K5fv290/6tGSVD4ZMsyWvRAb4GRYu2FSoTL82LXKNKwswdW0MlRqUN zdo+lE/zEw27/cwykcb1w7FZdRWt6P3ItVbVIoyLJkaCV33lVXpDEE878M3KiIukiB lu4r9a1zFPCcZSHEh31QKFi1xfC+JiWNq47UBeAA= Date: Tue, 11 Apr 2023 17:26:17 -0700 From: Andrew Morton To: Liu Shixin Cc: Naoya Horiguchi , Tony Luck , Miaohe Lin , Mike Kravetz , Muchun Song , , Subject: Re: [PATCH -next] mm: hwpoison: support recovery from HugePage copy-on-write faults Message-Id: <20230411172617.13bc444955f51653b170f744@linux-foundation.org> In-Reply-To: <20230411092741.780679-1-liushixin2@huawei.com> References: <20230411092741.780679-1-liushixin2@huawei.com> X-Mailer: Sylpheed 3.7.0 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: 15DF44001A X-Stat-Signature: 9kdfktzz9zpzodytb71kaa8u7xnphde9 X-Rspam-User: X-Rspamd-Server: rspam08 X-HE-Tag: 1681259179-262690 X-HE-Meta: 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 YSNChaIq ObqSloU37Gxs7hCwXQdVUU4vyMwjD+v/vGYcPeolkvv2HaOCStWGYMwsu9Iqmt0IZuoYyNe68Xj7Lrm2DLKrygczqqgG4M7o5jtfAYZT+R9Nf1t7MmyVzD1Zl9yfQ+R9qMNTfo/hX9rhIkSJMLfH62vfmgrrC7RN0iN/LWO0B9dLuU5KXd6IZOEA4t+NSAWIu08wrIoypnBRUeSFS1QRUnqk8YtuLLxxgmGmMv1WEQb3gYIjPj1EgJE4/Xdwo51owKe1gCaW0aUq1cwysp3A7Pr99uQCfFrFu9Kb3nEcqLxvSP4LNx1cIcJfkclw2jksgJizFOhje8z9hUyE+mgRIdQFQ4P+JOhUdgZEXsF5FS7rkjhvAy5/OvHZbgQ== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Tue, 11 Apr 2023 17:27:41 +0800 Liu Shixin wrote: > Patch a873dfe1032a ("mm, hwpoison: try to recover from copy-on write faults") > introduced a new copy_user_highpage_mc() function, and fix the kernel crash > when the kernel is copying a normal page as the result of a copy-on-write > fault and runs into an uncorrectable error. But it doesn't work for HugeTLB. What does "doesn't work" mean? Please fully describe the user-visible effects of the issue which this patch is addressing. > This is to support HugeTLB by using copy_mc_user_highpage() in copy_subpage() > and copy_user_gigantic_page() too. > > Moreover, this is also used by userfaultfd, it will return -EHWPOISON if > running into an uncorrectable error.