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h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=UBWAu1LednunpDwWyA6dN/T5o++Ac0xIHSNyHI2q6aNwwGBoDzmOu5fPBEFc8ArbW /tt8/W2BQ1vmQ4IAz1Nyb104x9b2KteD0nGMUiIeCt12QtQa7PBYD6YBCnrGAnBc3/ Qn0JhNAhnoCOhZV98otZjkfHLqNDdxzdtqE+wUKrNuac+jsIeeqfsfsGAH/ne5A61+ fJVgnYxkRNIdWQ6FVublLLmG5wjH46QN/ie1gMaNbSwwI4m4daasyct7wC0Ne/pUUf lpUvTiLRC205Aa4QBlQdiUIjcR8HkRzg6GlsEj28ZWB+3Gdl+rXI9orww+F0KE4FtQ tusBXnMM4yTlA== Date: Mon, 27 Oct 2025 12:42:09 +0100 From: =?utf-8?B?SsO2cmcgUsO2ZGVs?= To: Mostafa Saleh Cc: linux-mm@kvack.org, iommu@lists.linux.dev, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, corbet@lwn.net, 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 Subject: Re: [RFC PATCH 1/4] drivers/iommu: Add page_ext for IOMMU_DEBUG_PAGEALLOC Message-ID: References: <20251003173229.1533640-1-smostafa@google.com> <20251003173229.1533640-2-smostafa@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20251003173229.1533640-2-smostafa@google.com> X-Rspam-User: X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: C249C80010 X-Stat-Signature: mouijbbrz87y9311x3tufzhwnqcddcbo X-HE-Tag: 1761565332-938334 X-HE-Meta: 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 gcYRyvQ/ hp+e2jF4vJuVLnpVIUCAC4MLv1A== 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 Fri, Oct 03, 2025 at 05:32:26PM +0000, Mostafa Saleh wrote: > +config IOMMU_DEBUG_PAGEALLOC > + bool "Debug page memory allocations against IOMMU" > + depends on DEBUG_PAGEALLOC && IOMMU_API && PAGE_EXTENSION > + help > + This config checks when a page is freed by the kernel > + it's not mapped in any IOMMU domain. It can help with > + debugging use-after-free from driver doing DMA. > + This santaizer can have false-negative cases where some > + problems won't be detected. > + Expect overhead when enabling this + enabling the kernel > + command line iommu.debug_pagealloc. > + > + If unsure, say N here. Expected indentation here is and not . > --- /dev/null > +++ b/drivers/iommu/iommu-debug.c Is there a plan for this file to contain more than page-alloc debugging? If not, it should get a more specific name, like iommu-debug-pagealloc.c or similar.