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Sat, 08 Mar 2025 19:27:28 +0800 Message-ID: <0f4dfbde-74a5-451d-8764-cc7767596654@linux.alibaba.com> Date: Sat, 8 Mar 2025 19:27:26 +0800 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v4 1/3] x86/mce: Use is_copy_from_user() to determine copy-from-user context To: Borislav Petkov , "Luck, Tony" Cc: "peterz@infradead.org" , "catalin.marinas@arm.com" , "yazen.ghannam@amd.com" , "akpm@linux-foundation.org" , "linmiaohe@huawei.com" , "nao.horiguchi@gmail.com" , "tglx@linutronix.de" , "mingo@redhat.com" , "dave.hansen@linux.intel.com" , "x86@kernel.org" , "hpa@zytor.com" , "jpoimboe@kernel.org" , "linux-edac@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "linux-mm@kvack.org" , "baolin.wang@linux.alibaba.com" , "tianruidong@linux.alibaba.com" References: <20250307054404.73877-1-xueshuai@linux.alibaba.com> <20250307054404.73877-2-xueshuai@linux.alibaba.com> <20250307204018.GAZ8tZstt11Y4KFprC@fat_crate.local> <20250307224645.GKZ8t3VX5a5FhqNyZG@fat_crate.local> <20250307232230.GMZ8t_tja324AQqYME@fat_crate.local> From: Shuai Xue In-Reply-To: <20250307232230.GMZ8t_tja324AQqYME@fat_crate.local> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Rspamd-Server: rspam12 X-Rspam-User: X-Rspamd-Queue-Id: C061E180006 X-Stat-Signature: zbbpouoi9yc5oy43mkmm9yaqpnatqp44 X-HE-Tag: 1741433253-273926 X-HE-Meta: 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 jSpPvA7Y 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.051318, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: 在 2025/3/8 07:22, Borislav Petkov 写道: > On Fri, Mar 07, 2025 at 11:11:26PM +0000, Luck, Tony wrote: >> As for "explicit markup" I don't think it would be better to decorate >> every get_user() and copy_from_user() with some "this one can >> recover from #MC" > > I don't mean every function - I mean what we had there with EX_TYPE_UACCESS. > That is explicit and unambiguous. Proving that is_copy_from_user() is always > correct is a lot harder. > >> Note also that "what we had recently" was fragile, broke, and resulted >> in this regression. > > Because those exception types got renamed? Oh well, that should've been > reverted actually but no one involved realized that MCE is using those. > > And I'm not saying this is the only way to solve this. We could do something > like collecting all addresses on which an MCE can be recoverable, for example. > We haven't considered it that important... yet. > > Looks like we're going to try this new is_copy_from_user() thing now and then > see where it gets us. > > So, after the commit message has been fixed: > > Acked-by: Borislav Petkov (AMD) > > I'm presuming, this is going through akpm... > Thanks. Shuai