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Peter Anvin" , Andy Lutomirski , Dave Hansen , Fei Li , Nathan Chancellor , Wupeng Ma , Ingo Molnar Subject: Re: [PATCH v2 2/3] x86/mm/pat: fix VM_PAT handling in COW mappings Message-Id: <20240403151249.0f4fc5b4f8c07630fbbb6338@linux-foundation.org> In-Reply-To: <20240403212131.929421-3-david@redhat.com> References: <20240403212131.929421-1-david@redhat.com> <20240403212131.929421-3-david@redhat.com> 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-Rspamd-Server: rspam09 X-Rspamd-Queue-Id: D6A151C0002 X-Stat-Signature: 76n9sj4kdkw44ybxto5fuiymgookxsap X-Rspam-User: X-HE-Tag: 1712182371-282778 X-HE-Meta: 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 DEGkMdDZ kee4wzEE7yo9SvQxjkaC4vmVStkMSmi1kWezMyHHcHmAfNGPfyqC6p9rqJ5b558wcFivZF4PmeGueKHWgO2g8vDs2S+6NF/vwXnA8AomrdAhmjgn4FkvW04s5y0nKHm5KdCsVLsZ1JVD/gXjTpXqezaW4TNsaMeRqVq3TvzmcAJ9KGNBD3PUtEanLj4RNQNvaxRt6Jix0CkmnSQyoYB/cv6q8O40kArb2lD0BqpptTJJCqYc8fwc5MG7gY8H0cDw1O9Zsc1AAVaNLaPVJdBOeHqFwWRviBz6BcFtgEQFBXXORfxdFi5Fze1+fAolj9iP5llGycVA9Zah0CwL2hEFC9WpuKCTi3ZNW5GzZleVRQHq7U4GK2wNl0bp1dog4pXpuB7RB 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: List-Subscribe: List-Unsubscribe: On Wed, 3 Apr 2024 23:21:30 +0200 David Hildenbrand wrote: > PAT handling won't do the right thing in COW mappings: the first PTE > (or, in fact, all PTEs) can be replaced during write faults to point at > anon folios. Reliably recovering the correct PFN and cachemode using > follow_phys() from PTEs will not work in COW mappings. > > ... > > Reported-by: Wupeng Ma > Closes: https://lkml.kernel.org/r/20240227122814.3781907-1-mawupeng1@huawei.com > Fixes: b1a86e15dc03 ("x86, pat: remove the dependency on 'vm_pgoff' in track/untrack pfn vma routines") > Fixes: 5899329b1910 ("x86: PAT: implement track/untrack of pfnmap regions for x86 - v3") These are really old. Should we backport this?