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Howlett" , Andrew Morton , maple-tree@lists.infradead.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, "Paul E. McKenney" , syzbot+036af2f0c7338a33b0cd@syzkaller.appspotmail.com Subject: Re: [PATCH] maple_tree: Remove rcu_read_lock() from mt_validate() Message-ID: References: <20240820175417.2782532-1-Liam.Howlett@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240820175417.2782532-1-Liam.Howlett@oracle.com> X-Rspam-User: X-Rspamd-Queue-Id: 660C740008 X-Rspamd-Server: rspam01 X-Stat-Signature: to3srfxfp1nxxzia7uos7ixifh7ijuku X-HE-Tag: 1724194445-116780 X-HE-Meta: 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 wkxg940S BfMUDctKmBFCsOgay4AeGy9bjWAchB8fFIOWeflGoowHkZeAoivQR8NCUDoi1molLtcLKjyf0wdDDli2DNhNhxDmCntBrA7ECUn8TOBAFfj+rgocDgQbxACwz7BWsddCHE6IEXJvq0ijXuVGPe96Cb4ILNARpeA3ptVYD1AhoRvEIys948eUc44wOmjVQaCKzMF+W+Rz5Vhqo0yvIIst72qCfHh/01ODQPBYGkRoHZqXCO7tLeRftIywGU2cJVs5JF1ozYd/yEXadegp/OTmHcX8I6vrAsu3SYqtaeEhXA1doHwmkGAvOajketz4HqDqzmF+Z6H7ZnXM26SZqu7yZ+M9HI8UFKlZVG0nqb7eCJUmbNBfqMcjomscsOG14d21zDsFqzjX1CXjePa8= 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 21, 2024 at 06:38:45AM +0800, Hillf Danton wrote: Hillf, your email client is STILL broken. It's using the same message ID as the email it's replying to, which causes all kinds of problems. Please fix it or change to a different client. > On Tue, 20 Aug 2024 13:54:17 -0400 "Liam R. Howlett" > > > > The write lock should be held when validating the tree to avoid updates > > racing with checks. Holding the rcu read lock during a large tree > > validation may also cause a prolonged rcu read window. > > > >From the rcu stall's view, holding spin lock plays the same role of rcu > read lock, so what are you fixing by simply dropping rcu read lock? He's not holding a spinlock, he's holding a mutex, which has very different properties.