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Peter Anvin" , Linus Torvalds Subject: Re: [PATCH v2] x86/mm/pat: (un)track_pfn_copy() fix + doc improvements Message-ID: References: <20250408085950.976103-1-david@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250408085950.976103-1-david@redhat.com> X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: 6784C40005 X-Stat-Signature: boajmsytuhp5h87zf7okzx46ukfqn8cc X-Rspam-User: X-HE-Tag: 1744194735-539674 X-HE-Meta: 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 bOJnNuXo JVOA2w9KIOwV63oBG5O3VOwsN/dn1N5oreonFPxV/8Qmau9ahGgTw6wZnf23hbcASQONuM+wZ02DgsbNEL+rvKE2s5sZ/FonAxMzSU7GvdiKqtH+wDFW+ORxyyco7STjzxIx4dMRGOWwoYzvv7SU2YPXfFW/aKaHVFC0Tcg39SebXkzGVJpEKnhHLFD+qyKt/cbtpGTJSRDsXKyiq3b3LxwFWS1tbjfvCIsS6PxI2c71mB36cEfiyQz258/H6j78+dHGE14f9Pp6YvIeHNw/fZ1l8Y6Fe7cuicSJ1 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: * David Hildenbrand wrote: > We got a late smatch warning and some additional review feedback. > > smatch warnings: > mm/memory.c:1428 copy_page_range() error: uninitialized symbol 'pfn'. > > We actually use the pfn only when it is properly initialized; however, > we may pass an uninitialized value to a function -- although it will not > use it that likely still is UB in C. > > So let's just fix it by always initializing pfn in the caller of > track_pfn_copy(), and improving the documentation of track_pfn_copy(). > > While at it, clarify the doc of untrack_pfn_copy(), that internal checks > make sure if we actually have to untrack anything. Note that the title isn't accurate anymore, it's not an 'x86/mm/pat' patch, but an 'mm' patch. Thanks, Ingo