Path: csiph.com!news.mixmin.net!aioe.org!bofh.it!news.nic.it!robomod From: "Winkler, Tomas" Newsgroups: linux.kernel Subject: RE: [PATCH] tpm: don't destroy chip device prematurely Date: Mon, 03 Oct 2016 19:20:02 +0200 Message-ID: References: X-Extloop1: 1 X-Ironport-Av: E=Sophos;i="5.31,438,1473145200"; d="scan'208";a="1039760674" Thread-Topic: [PATCH] tpm: don't destroy chip device prematurely Thread-Index: AQHSHJY7jYiWgZcWb0y7/x76d69Sl6CUwviAgAC3bgCAANJWAIAAZjoAgABDzFA= Accept-Language: en-US Content-Language: en-US X-Ctpclassification: CTP_IC X-Titus-Metadata-40: eyJDYXRlZ29yeUxhYmVscyI6IiIsIk1ldGFkYXRhIjp7Im5zIjoiaHR0cDpcL1wvd3d3LnRpdHVzLmNvbVwvbnNcL0ludGVsMyIsImlkIjoiZjg2MGQwYzQtY2RjYi00NjQwLTkwMDgtYmE5MTQ4NDc0MDg1IiwicHJvcHMiOlt7Im4iOiJDVFBDbGFzc2lmaWNhdGlvbiIsInZhbHMiOlt7InZhbHVlIjoiQ1RQX0lDIn1dfV19LCJTdWJqZWN0TGFiZWxzIjpbXSwiVE1DVmVyc2lvbiI6IjE1LjkuNi42IiwiVHJ1c3RlZExhYmVsSGFzaCI6ImVDaEFcL3NEVWFyQXZvT2xjdGtuXC9TSHhpUU44WEdvaHlnUTc0ejhuT1hKMD0ifQ== X-Originating-IP: [10.184.70.10] Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 8BIT MIME-Version: 1.0 Sender: robomod@news.nic.it List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Approved: robomod@news.nic.it Lines: 27 Organization: linux.* mail to news gateway X-Original-Cc: Jarkko Sakkinen , "tpmdd-devel@lists.sourceforge.net" , "linux-kernel@vger.kernel.org" X-Original-Date: Mon, 3 Oct 2016 17:16:18 +0000 X-Original-Message-ID: <5B8DA87D05A7694D9FA63FD143655C1B542F474C@hasmsx108.ger.corp.intel.com> X-Original-References: <1475393971-12715-1-git-send-email-tomas.winkler@intel.com> <20161002101755.GA25844@intel.com> <20161002102455.GA27464@intel.com> <20161002212126.GA25872@obsidianresearch.com> <5B8DA87D05A7694D9FA63FD143655C1B542F466B@hasmsx108.ger.corp.intel.com> <20161003160008.GE5722@obsidianresearch.com> X-Original-Sender: linux-kernel-owner@vger.kernel.org Xref: csiph.com linux.kernel:1494976 > On Mon, Oct 03, 2016 at 07:05:48AM +0000, Winkler, Tomas wrote: > > > > This patch is wrong, I though the comments were clear. All entry > > > points to find the device must be deleted before we commit to shutting > down the device. > > > > > > You need to figure out some other way to solve your problem. > > > > Please be more specific regarding flows you think will be wrong with > > this patch, you must agree that the current code is broken even w/o > > runtime pm. > > No, I don't agree. Accessing dev->name is OK after the device_del. But you cannot assume that just dev->name is accessed and and runtime_pm breaks this assumption.. > > > What devicde_del does is fence off all sorts of ways to access the device, eg > sysfs files, bus registrations, etc, etc. That absolutely must be done before > calling tpm_suspend. But tpm2_shutdown is acceded via tpm_chip , we cannot call device_del before, this is just wrong from the Linux device mode perspective, we have to use other means to close the access to the device. Thanks Tomas