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b=dnfY5pRAIGrV1WNGoDYcWXmuVbKeJ+WGHuyKJSOYb0WR11KrcWMswcDa6njQ1BRXL s7/bqbGvvZZRBV1zjeK2PNoR4QLlBDZpWjwMk2TSqqcxt05s82Hge6O51FtWov3Y0i 0pIabEjTiX0LpHmntrSA+leDJCveu03POPi2MdkewQIKlTV66P1ftiaNbfRstdbPz1 xlOnAwnBw6cy5PMhQryQAJiJ9vbEugKl1sCeF2QckqZRZ6JJF3GgNXvMbr7eP0yND8 9G5FstSlZHqd+f/eI6QaOVmB3tcLaRQwBCB1ikBMh5xdbz9ygUZoyZAnA8WulqYY3X NGGCfKkcLxUng== From: Pratyush Yadav To: Greg KH Cc: Vipin Sharma , 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, 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 In-Reply-To: <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> <2025081310-custodian-ashamed-3104@gregkh> Date: Wed, 13 Aug 2025 14:02:07 +0200 Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) MIME-Version: 1.0 Content-Type: text/plain X-Rspamd-Queue-Id: 1794D18000D X-Rspam-User: X-Stat-Signature: 3ymxkqsa1m19ir5u9q7nykrjd1nr7amn X-Rspamd-Server: rspam09 X-HE-Tag: 1755086538-819964 X-HE-Meta: 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 ePJXOlXh fcalulQI1BA/nFMS8NzM3f15ZZHsRVODgw9gFIA8QQCHe5yNcoTGKhQ8KGtwtrWaxIh6vAuEiwfewn3Oiq681vdJHdUMPn63dcLNhRJhBI3kj5qZbA/pEif/O7YsufEbgPzN2gDF6G6OR5GgusrIiEfL7eYzPHN68FrqK99hMJVhFejiRmCmUpHJhuBOqtKNHhkJpORnaNbxLfRqP1PV5m3wF+F1+ppT11iyBFKp1OmIAz58= 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, Aug 13 2025, Greg KH wrote: > 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. Why would a WARN() crash the machine? That is what BUG() does, not WARN(). -- Regards, Pratyush Yadav