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h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=NocSEfYLe30ZRY2fHD2eMr9WqjHVuC9F/px//tLPS15SsrzoG9iv1HwM8iQDKE67S ZqIZrwB6jm/9KKfam0/4WZbDHX0t5+hxCiBriTSU8w8f0hqWmVGvbCFp0w4JQSDEvS 7dYDYI0kpYCmumRuzXCuANSWpidAV9iKz8KGjkmU= Date: Wed, 13 Aug 2025 09:09:54 +0200 From: Greg KH To: Vipin Sharma Cc: Pasha Tatashin , pratyush@kernel.org, jasonmiu@google.com, graf@amazon.com, changyuanl@google.com, rppt@kernel.org, dmatlack@google.com, rientjes@google.com, corbet@lwn.net, rdunlap@infradead.org, ilpo.jarvinen@linux.intel.com, kanie@linux.alibaba.com, ojeda@kernel.org, aliceryhl@google.com, masahiroy@kernel.org, akpm@linux-foundation.org, tj@kernel.org, yoann.congal@smile.fr, mmaurer@google.com, roman.gushchin@linux.dev, chenridong@huawei.com, axboe@kernel.dk, mark.rutland@arm.com, jannh@google.com, vincent.guittot@linaro.org, hannes@cmpxchg.org, dan.j.williams@intel.com, david@redhat.com, joel.granados@kernel.org, rostedt@goodmis.org, anna.schumaker@oracle.com, song@kernel.org, zhangguopeng@kylinos.cn, linux@weissschuh.net, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-mm@kvack.org, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org, hpa@zytor.com, rafael@kernel.org, dakr@kernel.org, bartosz.golaszewski@linaro.org, cw00.choi@samsung.com, myungjoo.ham@samsung.com, yesanishhere@gmail.com, Jonathan.Cameron@huawei.com, quic_zijuhu@quicinc.com, aleksander.lobakin@intel.com, ira.weiny@intel.com, andriy.shevchenko@linux.intel.com, leon@kernel.org, lukas@wunner.de, bhelgaas@google.com, wagi@kernel.org, djeffery@redhat.com, stuart.w.hayes@gmail.com, ptyadav@amazon.de, lennart@poettering.net, brauner@kernel.org, linux-api@vger.kernel.org, linux-fsdevel@vger.kernel.org, saeedm@nvidia.com, ajayachandra@nvidia.com, jgg@nvidia.com, parav@nvidia.com, leonro@nvidia.com, witu@nvidia.com Subject: Re: [PATCH v3 29/30] luo: allow preserving memfd Message-ID: <2025081310-custodian-ashamed-3104@gregkh> References: <20250807014442.3829950-1-pasha.tatashin@soleen.com> <20250807014442.3829950-30-pasha.tatashin@soleen.com> <20250813063407.GA3182745.vipinsh@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250813063407.GA3182745.vipinsh@google.com> X-Rspamd-Queue-Id: C31F2160008 X-Rspam-User: X-Stat-Signature: mh9w848nurdfxiuk497qe9umcoszzoyu X-Rspamd-Server: rspam09 X-HE-Tag: 1755068999-616154 X-HE-Meta: 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 91lcal2E FdhK1ZM+chYOPDBVoKs7OO3gR0tLURzMTgws8TFI/R0HEE0+6KwrLFkqo2wKE6k1egprTBQMlrYVqvz+pSPthL62aBfC/FefXglsv/qsCaMWx6lokmuhgzMsOpvWJIil7aowWUAF3NFAIkdVZD+zu1mnkUFeIUWwWavXJoHmChktlRrXbc/ZChxsDxQSAh97Yo6r10OuJVStkXrpnBkmLPdvX+EBmvcJ/+LTsoZNHYXUcqDu6vYuhSX9ewEsa6/7AAbchQGmfFc7BQ5HFVirTzh8tpHKDriF8nVFZmI6Nt5faUEXKMOLoBXGfPEfynhEeGRPbWeijFkMzMYhcQH6NetaiBlfSDjEiOSxG+L8LGmDLnvEw+FkJE8RQKFMRchijAUjjeAKoqJMYRWM= 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 Tue, Aug 12, 2025 at 11:34:37PM -0700, Vipin Sharma wrote: > On 2025-08-07 01:44:35, Pasha Tatashin wrote: > > From: Pratyush Yadav > > +static void memfd_luo_unpreserve_folios(const struct memfd_luo_preserved_folio *pfolios, > > + unsigned int nr_folios) > > +{ > > + unsigned int i; > > + > > + for (i = 0; i < nr_folios; i++) { > > + const struct memfd_luo_preserved_folio *pfolio = &pfolios[i]; > > + struct folio *folio; > > + > > + if (!pfolio->foliodesc) > > + continue; > > + > > + folio = pfn_folio(PRESERVED_FOLIO_PFN(pfolio->foliodesc)); > > + > > + kho_unpreserve_folio(folio); > > This one is missing WARN_ON_ONCE() similar to the one in > memfd_luo_preserve_folios(). So you really want to cause a machine to reboot and get a CVE issued for this, if it could be triggered? That's bold :) Please don't. If that can happen, handle the issue and move on, don't crash boxes. thanks, greg k-h