From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-oi1-f177.google.com (mail-oi1-f177.google.com [209.85.167.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C911922094 for ; Thu, 4 Jan 2024 12:37:30 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=ziepe.ca Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=ziepe.ca Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=ziepe.ca header.i=@ziepe.ca header.b="BudWBaX3" Received: by mail-oi1-f177.google.com with SMTP id 5614622812f47-3ba14203a34so328555b6e.1 for ; Thu, 04 Jan 2024 04:37:30 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ziepe.ca; s=google; t=1704371849; x=1704976649; darn=vger.kernel.org; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=Hf/WO7dpSxOwRzBOXg5oe62I+hQuDL4PKjYM4SM/3gc=; b=BudWBaX3rXZ32flH1YDE5MSwR7DrNYSqH9VGDWO4+Q8Dbcjv1ERLA6gUQxGrS640Sk PKEviOs5cGxil6ziJXC8nIi4Ft4AKnlB+aYO8JDuhrAa9lF5UuD760w2M582j30isq+3 IqGjiiSjE+t6Iuhai2axIhLEqUbZYe9gVG/tzzWbRPnbIjcS+3nJhTfouevW2DHFR7U8 Q0YvHZ5jL1OULtv7kALZ6R6FOV8kWJhcRfS4v4er7iaUQd0S/uttoc62azUQfPALoMEE 7xBuRFNGL+0xj6LlJTUDT4B8lQLAw+xEO+FbpeuETIo/IA27imMPEMJGeDDO04e0Facf 2JUA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1704371849; x=1704976649; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=Hf/WO7dpSxOwRzBOXg5oe62I+hQuDL4PKjYM4SM/3gc=; b=OvzssnN9LOQSih4035lkqVpcnZ97NkJSPtlEzVf9ZsK2KKjsXq40Ae4u4xnIYY4zvw PeQCDqUGX8o8JMLZSkBLJC1Ixzp6J73WJoRGpdPKIhu+mgvyRmSah1AjgkQMDV9mlxfT RbzAKbfI2riYWj0EZAB6WL0uWrX+Aqm0r2OhHhptY2e9sSfIekYWCIV6MVFdfxp2ievN 6OOvm0dV+9SNQ86AgFD2pef3DDU5nAY7IYaKr80FrOA5sXYRxRvgPKIkfXzla1I5a2EF DLogLhriyvzwDuhAzjlTkcyNNJluhUASBPEZtVJkBD1VEiVEIE6y6szXLaZnnAuJzHEu hHgw== X-Gm-Message-State: AOJu0YyXMiR/BCycp3rbayjM7JWkKMFZBQFVyoMH6mv2QzyAgaACCBDT AdD4cOj7F8Rt4W+BnI4R5qOVIsopgVfeNg== X-Google-Smtp-Source: AGHT+IGHenxmOLwVI1m0q3Nd7JBq+/yjCUMw/euLk5orZbJN6ioJA9VMp0JTTfG1Gf+gJgKnh1+Khg== X-Received: by 2002:a05:6808:2918:b0:3bb:d7ff:982d with SMTP id ev24-20020a056808291800b003bbd7ff982dmr462984oib.98.1704371849776; Thu, 04 Jan 2024 04:37:29 -0800 (PST) Received: from ziepe.ca (hlfxns017vw-142-68-80-239.dhcp-dynamic.fibreop.ns.bellaliant.net. [142.68.80.239]) by smtp.gmail.com with ESMTPSA id z8-20020ad44148000000b0067f7e41de80sm11660650qvp.46.2024.01.04.04.37.28 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 04 Jan 2024 04:37:28 -0800 (PST) Received: from jgg by wakko with local (Exim 4.95) (envelope-from ) id 1rLMyW-0017pG-9U; Thu, 04 Jan 2024 08:37:28 -0400 Date: Thu, 4 Jan 2024 08:37:28 -0400 From: Jason Gunthorpe To: Shifeng Li Cc: leon@kernel.org, wenglianfa@huawei.com, gustavoars@kernel.org, linux-rdma@vger.kernel.org, linux-kernel@vger.kernel.org, Shifeng Li , "Ding, Hui" Subject: Re: [PATCH] RDMA/device: Fix a race between mad_client and cm_client init Message-ID: <20240104123728.GC50608@ziepe.ca> References: <20240102034335.34842-1-lishifeng@sangfor.com.cn> <20240103184804.GB50608@ziepe.ca> <80cac9fd-7fed-403e-8889-78e2fc7a49b0@sangfor.com.cn> Precedence: bulk X-Mailing-List: linux-rdma@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <80cac9fd-7fed-403e-8889-78e2fc7a49b0@sangfor.com.cn> On Thu, Jan 04, 2024 at 02:48:14PM +0800, Shifeng Li wrote: > The root cause is that mad_client and cm_client may init concurrently > when devices_rwsem write semaphore is downgraded in enable_device_and_get() like: That can't be true, the module loader infrastructue ensures those two things are sequential. You are trying to say that the post-client fixup stuff will still see the DEVICE_REGISTERED before it reaches the clients_rwsem lock? That probably just says the clients_rwsem should be obtained before changing the DEVICE_STATE too :\ Jason