From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jason Gunthorpe Subject: Re: [PATCH] tpm: fix rollback/cleanup before tpm_chip_register() Date: Tue, 2 Feb 2016 16:13:53 -0700 Message-ID: <20160202231353.GA32711@obsidianresearch.com> References: <1454205942-13033-1-git-send-email-jarkko.sakkinen@linux.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <1454205942-13033-1-git-send-email-jarkko.sakkinen-VuQAYsv1563Yd54FQh9/CA@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: tpmdd-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org To: Jarkko Sakkinen Cc: tpmdd-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, stable-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: tpmdd-devel@lists.sourceforge.net On Sat, Jan 30, 2016 at 06:05:42PM -0800, Jarkko Sakkinen wrote: > The release-callback is not used before the device is attached to the > device hierarchy. This caused resources not to cleanup properly if the > device driver initialization failed before tpm_chip_register(). This commentary is not right, the release callback is callable immediately after device_initialize returns, it will be called by the last put_device(). > - * tpmm_chip_alloc() - allocate a new struct tpm_chip instance > - * @dev: device to which the chip is associated > + * tpmm_chip_alloc() - allocate and initialize a TPM chip > + * @pdev: the platform device who is the parent of the chip ? A platform device is not required, just something in a state that can handle devm. > + /* Associate character device with the platform device only after > + * it is properly initialized. > + */ > + dev_set_drvdata(pdev, chip); > + devm_add_action(pdev, (void (*)(void *)) tpm_dev_release, > &chip->dev); No, a release function can never be called naked. The action needs to do put_device, which is the error unwind for device_initialize(). > @@ -162,7 +165,10 @@ static int tpm_add_char_device(struct tpm_chip *chip) > MINOR(chip->dev.devt), rc); > > cdev_del(&chip->cdev); > - return rc; > + } else { > + devm_remove_action(chip->dev.parent, > + (void (*)(void *)) tpm_dev_release, > + &chip->dev); This is in the wrong place, the devm should be canceled only if tpm_chip_register returns success, at that point the caller's contract is to guarentee a call to tpm_chip_unregister, and tpm_chip_unregister does the put_device that calls the release function. Jason ------------------------------------------------------------------------------ Site24x7 APM Insight: Get Deep Visibility into Application Performance APM + Mobile APM + RUM: Monitor 3 App instances at just $35/Month Monitor end-to-end web transactions and take corrective actions now Troubleshoot faster and improve end-user experience. Signup Now! http://pubads.g.doubleclick.net/gampad/clk?id=267308311&iu=/4140