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Peter Anvin" , Tony Luck , Andy Lutomirski , Peter Zijlstra , Andrew Morton , Naoya Horiguchi , linux-kernel@vger.kernel.org, linux-edac@vger.kernel.org, linux-mm@kvack.org, Guohanjun Subject: Re: [PATCH -next v5 2/3] x86/mce: set MCE_IN_KERNEL_COPYIN for DEFAULT_MCE_SAFE exception Message-ID: <20240327220511.GCZgSYF6lJ3U1CaKV0@fat_crate.local> References: <20240204082627.3892816-1-tongtiangen@huawei.com> <20240204082627.3892816-3-tongtiangen@huawei.com> <20240207122942.GRZcN3tqWkV-WE-pak@fat_crate.local> <100198dd-320f-68e6-9c09-210620940a74@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <100198dd-320f-68e6-9c09-210620940a74@huawei.com> X-Rspamd-Queue-Id: 8FE59160024 X-Rspam-User: X-Rspamd-Server: rspam05 X-Stat-Signature: uk3w7ydwzc5q6nfbn1s9njuuj41uiiqt X-HE-Tag: 1711577141-586713 X-HE-Meta: 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 x/0Mnsoq 9+5gLXX8wJs/i7KzEhC0ZB7jJfX3s7oSxWDo7EADiXzS7PttlQX1lYF0XyVFXCxkyU4mg3QSdOYoZ4+ggm2c3kv7WpJzwK4LabktF1RCzIdBNrJa4defqkiXFPfBJYUCCHWbujbcc41qhhD8L819bxFMqDaD0lcGhfUZUZlRa8P+1JE4WcD8EnpPnVJbYxQOqxZNk/bmQO2ETmuaBnL7iScCxKguwiRGGyeWHEut+moOseb6+r0GPF6GnRN3iaqjRbMy7IgDQdxLgKuX48eecC+ughg== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000006, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Sun, Feb 18, 2024 at 06:08:14PM +0800, Tong Tiangen wrote: > 1. The copy_mc_to_kernel() is used in the coredump, KSM, and COW > scenarios, in these scenarios, the src mem stores the user data and the > kernel use kernel address to access the src mem(using kmap()). > > 2. the src mem of copy_mc_to_user() is currently only used by the DAX: You mean just because it currently is used somewhere which probably is ok - no clue what DAX does - and even if the source address is still *kernel* memory and even at the danger that someone else might use it in the future and think the handling on a potential #MC is ok, you're still arguing that this is the right thing to do perhaps because it fits your use case?! Sorry Tiangen, not gonna happen. -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette