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(p200300cbc707a1000e2041dac49b8974.dip0.t-ipconnect.de. [2003:cb:c707:a100:e20:41da:c49b:8974]) by smtp.gmail.com with ESMTPSA id w2-20020a5d6802000000b002c7163660a9sm12202423wru.105.2023.03.07.02.44.03 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 07 Mar 2023 02:44:05 -0800 (PST) Message-ID: Date: Tue, 7 Mar 2023 11:44:03 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.8.0 Subject: Re: [PATCH v7 21/41] mm: Add guard pages around a shadow stack. To: Borislav Petkov , "Edgecombe, Rick P" Cc: "bsingharora@gmail.com" , "hpa@zytor.com" , "Syromiatnikov, Eugene" , "peterz@infradead.org" , "rdunlap@infradead.org" , "keescook@chromium.org" , "Yu, Yu-cheng" , "dave.hansen@linux.intel.com" , "kirill.shutemov@linux.intel.com" , "Eranian, Stephane" , "linux-mm@kvack.org" , "fweimer@redhat.com" , "nadav.amit@gmail.com" , "jannh@google.com" , "dethoma@microsoft.com" , "kcc@google.com" , "linux-arch@vger.kernel.org" , "pavel@ucw.cz" , "oleg@redhat.com" , "hjl.tools@gmail.com" , "Yang, Weijiang" , "Lutomirski, Andy" , "linux-doc@vger.kernel.org" , "arnd@arndb.de" , "tglx@linutronix.de" , "Schimpe, Christina" , "mike.kravetz@oracle.com" , "x86@kernel.org" , "akpm@linux-foundation.org" , "debug@rivosinc.com" , "jamorris@linux.microsoft.com" , "john.allen@amd.com" , "rppt@kernel.org" , "andrew.cooper3@citrix.com" , "mingo@redhat.com" , "corbet@lwn.net" , "linux-kernel@vger.kernel.org" , "linux-api@vger.kernel.org" , "gorcunov@gmail.com" References: <20230227222957.24501-1-rick.p.edgecombe@intel.com> <20230227222957.24501-22-rick.p.edgecombe@intel.com> <20230307103251.GAZAcS0zpon573Ox3N@fat_crate.local> From: David Hildenbrand Organization: Red Hat In-Reply-To: <20230307103251.GAZAcS0zpon573Ox3N@fat_crate.local> X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Rspam-User: X-Rspamd-Queue-Id: AC251180014 X-Rspamd-Server: rspam01 X-Stat-Signature: 65xgw19u1btcsww56a1x8drrp8pjda3z X-HE-Tag: 1678185851-274110 X-HE-Meta: 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 zCp3y55u 0wGPtSNjEt0nhpPpkIrUPdBIdGcG1k+lFqFT9TH8l4fAVRE65HJF/c3wm/gq6oS4nnAIivrrb0jW8n0F91jPfEkMKtKD/R478kxGCSoya+JkrMJ7+PxxK13slL1vapAF6wX0TdrqQtwfW3rt3mfgRZEqWFLzMxC/KrbVwQKksx9jD5nCubmSi52bFLpcBGpUml/kkMu4VzEI93QbywoQ+rTz1JmUnP6HRQd4eTW9pAQd4xvhul8QB5Ws6JDJ/dEiWVREZJTxXnrq8kwe/vFhO/ZZfWKVc7jHIaqwCKsAGcqwj2PEcILUnIQL9/UWjyl/TTcfa6BeBnGTJqMnxY857pnxeE6xl5gE9aB3v8JuUPBs6F7Mbx/krYjz9fNOF8MErWD8hyWoxqTro/R9oLN5ha+DctklVtIkOOpy5FdH+nG7vA5tSEr5VPOocu7bOriDUWL3/Z0LveQiibgebPQy2bS1gAKyLjGWBQGN/l4GCJX3ECl4RQrYac0nAHhFXWoSw7Q4x 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 07.03.23 11:32, Borislav Petkov wrote: > On Tue, Mar 07, 2023 at 01:29:50AM +0000, Edgecombe, Rick P wrote: >> On Mon, 2023-03-06 at 09:08 +0100, Borislav Petkov wrote: >>> Just typos: >> >> All seem reasonable to me. Thanks. >> >> For using the log verbiage for the comment, it is quite big. Does >> something like this seem reasonable? > > Yeah, it does. I wouldn't want to lose that explanation in a commit > message. > > However, this special aspect pertains to the shstk implementation in x86 > but the code is generic mm and such arch-specific comments are kinda > unfitting there. > > I wonder if it would be better if you could stick that explanation > somewhere in arch/x86/ and only refer to it in a short comment above > VM_SHADOW_STACK check in stack_guard_start_gap()... +1 -- Thanks, David / dhildenb