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[209.85.208.50]) by smtp.gmail.com with ESMTPSA id a640c23a62f3a-b79f4498ed9sm461823266b.16.2025.12.05.13.56.34 for (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 05 Dec 2025 13:56:34 -0800 (PST) Received: by mail-ed1-f50.google.com with SMTP id 4fb4d7f45d1cf-6418b55f86dso4559876a12.1 for ; Fri, 05 Dec 2025 13:56:34 -0800 (PST) X-Received: by 2002:a05:6402:50ca:b0:640:a9fb:3464 with SMTP id 4fb4d7f45d1cf-6491a3e15e8mr281045a12.7.1764971793872; Fri, 05 Dec 2025 13:56:33 -0800 (PST) MIME-Version: 1.0 References: <20251203212918.82f1c9d3947940aeae263878@linux-foundation.org> In-Reply-To: <20251203212918.82f1c9d3947940aeae263878@linux-foundation.org> From: Linus Torvalds Date: Fri, 5 Dec 2025 13:56:17 -0800 X-Gmail-Original-Message-ID: X-Gm-Features: AQt7F2raveagspIXcILTjqryWuFYBWky6HLhbYqsd4miy0ZkeQl0CmPr-EtPev0 Message-ID: Subject: Re: [GIT PULL] MM updates for 6.19-rc1 To: Andrew Morton , Ankit Agrawal , Alex Williamson Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, mm-commits@vger.kernel.org Content-Type: text/plain; charset="UTF-8" X-Rspamd-Queue-Id: DD3C410000B X-Rspam-User: X-Rspamd-Server: rspam12 X-Stat-Signature: con3154h8jj56tmqajpy8drupc31bwze X-HE-Tag: 1764971796-55415 X-HE-Meta: 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 DW7M4KaG 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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: List-Subscribe: List-Unsubscribe: On Wed, 3 Dec 2025 at 21:29, Andrew Morton wrote: > > Ankit Agrawal: > vfio/nvgrace-gpu: register device memory for poison handling So I had to look at this one because there was a conflict ("int ret" had been removed by another commit), and after looking at it I ended up deciding to revert this patch entirely. I may be wrong, but that patch looks *COMPETELY* broken. It did nvgrace_gpu_mmap() -> nvgrace_gpu_vfio_pci_register_pfn_range() -> register_pfn_address_space() using &nvdev->resmem/usemem, and honestly, that looks mis-designed from beginning to end. If somebody maps the same BAR of that device twice, the second call to nvgrace_gpu_vfio_pci_register_pfn_range() will randomly overwrite a node (that "region->pfn_address_space.node") that has already been registered and inserted into the pfn_space_itree interval tree. You can't *do* things like this! Maybe I'm misreading this, and somebody should correct me, but it really looks like completely broken code to me. It basically seems to assume that those two bar regions are mapped exactly once, and I don't see why that would ever be true except by pure accident because you only have one user. That may be a common case, but that doesn't make any of this correct. Again - maybe I'm missing something. If so, that commit can be re-done with explanations of why it's all correct. Linus