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[209.132.183.28]) by mx.google.com with ESMTPS id s26si9942394vsm.30.2019.07.22.09.15.33 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 22 Jul 2019 09:15:33 -0700 (PDT) Received-SPF: pass (google.com: domain of mst@redhat.com designates 209.132.183.28 as permitted sender) client-ip=209.132.183.28; Authentication-Results: mx.google.com; spf=pass (google.com: domain of mst@redhat.com designates 209.132.183.28 as permitted sender) smtp.mailfrom=mst@redhat.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=redhat.com Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 8B3EEC057F88; Mon, 22 Jul 2019 16:15:32 +0000 (UTC) Received: from redhat.com (ovpn-124-54.rdu2.redhat.com [10.10.124.54]) by smtp.corp.redhat.com (Postfix) with SMTP id E40705D9D3; Mon, 22 Jul 2019 16:15:23 +0000 (UTC) Date: Mon, 22 Jul 2019 12:15:22 -0400 From: "Michael S. Tsirkin" To: Jason Gunthorpe Cc: "Paul E. McKenney" , 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: <20190722121441-mutt-send-email-mst@kernel.org> References: <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> <20190722160448.GH7607@ziepe.ca> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190722160448.GH7607@ziepe.ca> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.32]); Mon, 22 Jul 2019 16:15:32 +0000 (UTC) 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 01:04:48PM -0300, Jason Gunthorpe wrote: > 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?? Right it's all based on documentation saying we should worry :) > Sounds like the answer is "don't worry about it" ? > > Thanks, > Jason