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[2001:1c00:3405:d100:fd78:186a:9428:6b97]) by smtp.gmail.com with ESMTPSA id a640c23a62f3a-b842a233fdfsm272017666b.7.2026.01.06.08.49.06 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 06 Jan 2026 08:49:07 -0800 (PST) From: Boudewijn van der Heide To: liam.howlett@oracle.com Cc: akpm@linux-foundation.org, aliceryhl@google.com, andrewjballance@gmail.com, boudewijn@delta-utec.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, maple-tree@lists.infradead.org, willy@infradead.org Subject: Re: [PATCH] maple_tree: Add dead node check in mas_dup_alloc() Date: Tue, 6 Jan 2026 17:48:44 +0100 Message-ID: <20260106164844.280106-1-boudewijn@delta-utec.com> X-Mailer: git-send-email 2.47.3 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspam-User: X-Rspamd-Server: rspam09 X-Rspamd-Queue-Id: 2FE6B40005 X-Stat-Signature: m1sttbib8tw676d7pp5zowwbrffqdphn X-HE-Tag: 1767718148-387048 X-HE-Meta: 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 3WuFWRrs K+dPfroFx/3585CsdzVTuL+ygbLONJL6nAAm7P2bW9+oGvpU1pBnzqgMeDi0QPpKoRp5Rt+q45giTp7fujyU1d+au9usI/jP90fPBniuQNxH7FPeihXxXSabN6MWkSPtfQOsnqHhuxmuoTyf8Xu3c3o/XmIFw0UeiCs8oV07iS3Q9yDa/5TuxTDpOVGmoWynz6qNVBeKW4LwuiYffczVODQm1ohzA2lG2bgznuene9tOYpuMvoytKBTuQGWG5KOtsmMP4OhLvjwCISydq+7u6pUSquDmSqUaDSUL2Si+//Nvc5MBZNLTb+cW1hOJDAAwyBPXRA2dlGsbrBhuSOueakb3Iu7zdckHuIa3lyEgzr2M4IjyVxryS2DU6uZEEj+vLU8+Pw0LKMQYhxFTgNcMqgqTRdoVR64GEOPVDOG3hjH/vbk6tobO4xpOLgQRO7GJW2fx3VLGKArsIe++yEfv6YZT0UA== X-Bogosity: Ham, tests=bogofilter, spamicity=0.010238, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: > > > Surely this should just be a lockdep assertion that the appropriate > > > locks are held? > > > > > Just to confirm: do you want me to remove the original runtime check entirely > > and replace it with a lockdep_assert(), or do you want both? > > If it's only the assertion, > Please do not include any runtime checks in this change - Just the > lockdep_assert(). > > that would mean that production builds won't enforce the check, right? > > > > For v2, should I add a Fixes: line and Cc: stable, > > or should i leave it out? > This does not need to be backported and does not fix anything. It's an > attempt to protect the user from shooting their own foot off by using > the interface incorrectly. > The fact that no one in the tree uses it incorrectly means that any > backport would be for the benefit of out-of-tree drivers, which we do > not support. Thanks for the help and clarification! I will send v2 with just the assertion, as suggested. Thanks, Boudewijn