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c=relaxed/simple; d=linux-foundation.org; s=korg; t=1695228770; bh=yWtN60awfDt7GteEhvpp58Ui6/Sl180L8dtwE401MDg=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=qDFEmye3mEpHyEFjZ/18pAycjTaDmEm5EkG/lU/7CY0luxE8GuVOHCzjVYH+RJxfN qtoTu+YIB/B3SAEqzaDlgmhwN3TgVC49jh0rOw8JhZbetcbeebymbehTAHy/zgBvnc dLDWzsGlnXjSBat/IfRPMuT6Y/e6DllDqy3esO0I= Date: Wed, 20 Sep 2023 09:52:49 -0700 From: Andrew Morton To: "Matthew Wilcox (Oracle)" Cc: linux-mm@kvack.org, Yin Fengwei , Dave Hansen , David Hildenbrand , Thomas Gleixner , syzbot+55cc72f8cc3a549119df@syzkaller.appspotmail.com Subject: Re: [PATCH 2/2] mm: Abstract moving to the next PFN Message-Id: <20230920095249.4f832f7d670f4c5b1faeac74@linux-foundation.org> In-Reply-To: <20230920040958.866520-1-willy@infradead.org> References: <20230920035336.854212-1-willy@infradead.org> <20230920040958.866520-1-willy@infradead.org> X-Mailer: Sylpheed 3.8.0beta1 (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-Stat-Signature: m9w1tpcxndfhhjemo1pnnhyf4aqeggcz X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: 5D9BA14000E X-Rspam-User: X-HE-Tag: 1695228773-863588 X-HE-Meta: U2FsdGVkX1++wI+gL7w45I3LSnxpv8tPJ9uEN8eEofYLYmhEG1F9OJcozxLDrRu1iH/LaSK1Ox5HgBhd5e7IDX3EA+/ru5B+wWgw/qRTYGBMao98byoviL9n7LM6D9pKgCMeddHMK2u9beEmuMYIywX0jpa2EucjgRtZ2BNkXk8n6v4B2xR10dVX2Rh66RvKuK5Xl4NlEFxjEe8AQEnl6/6yFnb10ewwFjJF3iyBohgdHSBNFyTyaBMoL4fZB9la6RZplwa+3nIZ2n4Wh98f2sWiRM5/m7a0b3g4oRojeD+7cqnxjNzSxJoJoujOi4NbFhQVfn47Y08YOq5q/iA7aXh7r58Qseg8cGPAhC5kmTTi/Km4Gp4At9DqH3wY+WogbBlh1LnsHYS5tqN+KRb7O9BPQ1da65SJjp9sj7a5V9//FZz9ckfC5x2zF8fXCShigQFgxiSTeuIKgEvO4Mj46fWTv6aSiUj2uFXOLiE1k3NvCOXjrwe++8TiYzLSUIAJBbzmVQkh0AuAcKOGddXJMatpQn5EnSgAtV3y3iWOlTyT4UrjreA9+/Fdf/CkpFEK2D6dV4YL7OhwjDnrP9c3MNb+csYvh+5OeXz7PTaci90sFiVQ1kMKsJxlLOEmGk43YCC4NNDyc5QwZUWqhhSeC7xaynaxiDw3/Icrnh6k1qB+j+MBEqUWHtd4cpgOnavrdX36z6FTgvHrGmwzQbNXAJxidtOLJhOGbHc3SuzabQX/mEBJhYCC1bzVN9CzWJp5NNv17c+jT5VHuSLMsdOkczUNrxcBVfBBDLmCEwm/UHlRPkf3eBoWboquksY54O3xpBAmxFzU2X3WzL8p6VS5kfofe2DGi2giIG+HZuHLufGW3/mEGkhB5tulRIjG/1bfgR7hwX5yu48MJVha/bZr1cu01nb+YoqEsqnFv839niDadqrwv/RX0/mxG2fbaDhiqmPAAMjB703g8tmmYH3 U16VQ3rB 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 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 Wed, 20 Sep 2023 05:09:58 +0100 "Matthew Wilcox (Oracle)" wrote: > In order to fix the L1TF vulnerability, x86 can invert the PTE bits for > PROT_NONE VMAs, which means we cannot move from one PTE to the next by > adding 1 to the PFN field of the PTE. Abstract advancing the PTE to > the next PFN through a pte_next_pfn() function/macro. > > Signed-off-by: Matthew Wilcox (Oracle) > Fixes: bcc6cc832573 ("mm: add default definition of set_ptes()") > Reported-by: syzbot+55cc72f8cc3a549119df@syzkaller.appspotmail.com Is it just me, or is it a pain hunting down things via message IDs? I tweaked the changelog thusly, pointing out that this fixes a BUG. : In order to fix the L1TF vulnerability, x86 can invert the PTE bits for : PROT_NONE VMAs, which means we cannot move from one PTE to the next by : adding 1 to the PFN field of the PTE. This results in the BUG reported at : [1]. : : Abstract advancing the PTE to the next PFN through a pte_next_pfn() : function/macro. : : Link: https://lkml.kernel.org/r/20230920040958.866520-1-willy@infradead.org : Signed-off-by: Matthew Wilcox (Oracle) : Fixes: bcc6cc832573 ("mm: add default definition of set_ptes()") : Reported-by: syzbot+55cc72f8cc3a549119df@syzkaller.appspotmail.com : Closes: https://lkml.kernel.org/r/000000000000d099fa0604f03351@google.com [1]