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[156.34.55.100]) by smtp.gmail.com with ESMTPSA id y3sm20100502qtj.46.2019.07.22.09.04.49 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Mon, 22 Jul 2019 09:04:49 -0700 (PDT) Received: from jgg by mlx.ziepe.ca with local (Exim 4.90_1) (envelope-from ) id 1hpanw-00059A-U7; Mon, 22 Jul 2019 13:04:48 -0300 Date: Mon, 22 Jul 2019 13:04:48 -0300 From: Jason Gunthorpe To: "Paul E. McKenney" Cc: "Michael S. Tsirkin" , Matthew Wilcox , aarcange@redhat.com, akpm@linux-foundation.org, christian@brauner.io, davem@davemloft.net, ebiederm@xmission.com, elena.reshetova@intel.com, guro@fb.com, hch@infradead.org, james.bottomley@hansenpartnership.com, jasowang@redhat.com, jglisse@redhat.com, keescook@chromium.org, ldv@altlinux.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-parisc@vger.kernel.org, luto@amacapital.net, mhocko@suse.com, mingo@kernel.org, namit@vmware.com, peterz@infradead.org, syzkaller-bugs@googlegroups.com, viro@zeniv.linux.org.uk, wad@chromium.org Subject: Re: RFC: call_rcu_outstanding (was Re: WARNING in __mmdrop) Message-ID: <20190722160448.GH7607@ziepe.ca> References: <000000000000964b0d058e1a0483@google.com> <20190721044615-mutt-send-email-mst@kernel.org> <20190721081933-mutt-send-email-mst@kernel.org> <20190721131725.GR14271@linux.ibm.com> <20190721210837.GC363@bombadil.infradead.org> <20190721233113.GV14271@linux.ibm.com> <20190722035042-mutt-send-email-mst@kernel.org> <20190722115149.GY14271@linux.ibm.com> <20190722134152.GA13013@ziepe.ca> <20190722155235.GF14271@linux.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190722155235.GF14271@linux.ibm.com> User-Agent: Mutt/1.9.4 (2018-02-28) 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: On Mon, Jul 22, 2019 at 08:52:35AM -0700, Paul E. McKenney wrote: > So why then is there a problem? I'm not sure there is a real problem, I thought Michael was just asking how to design with RCU in the case where the user controls the kfree_rcu?? Sounds like the answer is "don't worry about it" ? Thanks, Jason