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Received: from [50.53.43.113] (helo=[192.168.254.34]) by bombadil.infradead.org with esmtpsa (Exim 4.98.2 #2 (Red Hat Linux)) id 1vH5zn-0000000GBF5-3TGi; Thu, 06 Nov 2025 19:50:11 +0000 Message-ID: <55391dad-339b-47f8-8996-afe337b238e0@infradead.org> Date: Thu, 6 Nov 2025 11:50:11 -0800 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 1/4] drivers/iommu: Add page_ext for IOMMU_DEBUG_PAGEALLOC To: Mostafa Saleh , linux-mm@kvack.org, iommu@lists.linux.dev, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org Cc: corbet@lwn.net, joro@8bytes.org, will@kernel.org, robin.murphy@arm.com, akpm@linux-foundation.org, vbabka@suse.cz, surenb@google.com, mhocko@suse.com, jackmanb@google.com, hannes@cmpxchg.org, ziy@nvidia.com, david@redhat.com, lorenzo.stoakes@oracle.com, Liam.Howlett@oracle.com, rppt@kernel.org, Qinxin Xia References: <20251106163953.1971067-1-smostafa@google.com> <20251106163953.1971067-2-smostafa@google.com> Content-Language: en-US From: Randy Dunlap In-Reply-To: <20251106163953.1971067-2-smostafa@google.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam09 X-Rspamd-Queue-Id: 7B3E94000A X-Stat-Signature: xg7w74wa4pdqxngyqzmb5kkp855enjnx X-Rspam-User: X-HE-Tag: 1762458618-115855 X-HE-Meta: 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 29hX6MGW WvuoDdL3ivi+AWnxo5IYd66ek2fg4JrYrmbM5EQ7/ETxNeKDIhk59tjGe1p/ywUMHUbImE5C4RGUphrmRZlb0ajtlbXHuLMpj3bJt/d+Oi3Dbq8mJpQkoACuuufstc3+A8cORsv640odV7PW+N0tb+NyMAsQCbR6XAgxT2wsomFUWajXvuAM8s/1gegRxlgb03V1nyZPkUZDkpp1oQq2IX2COBpAfibe6nBkkJFIrqQj1dFZzOjnY0AmtJejkTOroXoPeoQi5EwNDen8qF71d/U1E8AQs18wj/dbIV9r7zctH8LOIQXMEzb8xKHKTnN42/2knNqDYCj67F3pXGHvjnylERQ== 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: > diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig > index 70d29b14d851..6b5e9a2d936a 100644 > --- a/drivers/iommu/Kconfig > +++ b/drivers/iommu/Kconfig > @@ -383,4 +383,19 @@ config SPRD_IOMMU > > Say Y here if you want to use the multimedia devices listed above. > > +config IOMMU_DEBUG_PAGEALLOC > + bool "Debug page memory allocations against IOMMU" > + depends on DEBUG_PAGEALLOC && IOMMU_API && PAGE_EXTENSION > + help > + This config checks that a page is freed(unmapped) or mapped by the > + kernel is not mapped in any IOMMU domain. It can help with debugging > + use-after-free or out-of-bound maps from drivers doing DMA through > + the IOMMU API. > + This santaizer can have false-negative cases where some problems sanitizer > + won't be detected. > + Expect overhead when enabling this and enabling the kernel command > + line iommu.debug_pagealloc. > + > + If unsure, say N here. > + > endif # IOMMU_SUPPORT -- ~Randy