From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752240AbbCAVzy (ORCPT ); Sun, 1 Mar 2015 16:55:54 -0500 Received: from mga09.intel.com ([134.134.136.24]:50911 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751202AbbCAVzx (ORCPT ); Sun, 1 Mar 2015 16:55:53 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.09,672,1418112000"; d="scan'208";a="658925907" From: Jarkko Sakkinen To: Peter Huewe , Ashley Lai , Marcel Selhorst Cc: tpmdd-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org, christophe.ricard@gmail.com, jason.gunthorpe@obsidianresearch.com, stefanb@linux.vnet.ibm.com, Jarkko Sakkinen Subject: [PATCH] tpm: fix call order in tpm-chip.c Date: Sun, 1 Mar 2015 23:55:47 +0200 Message-Id: <1425246947-3336-1-git-send-email-jarkko.sakkinen@linux.intel.com> X-Mailer: git-send-email 2.1.4 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org - tpm_dev_add_device(): cdev_add() must be done before uevent is propagated in order to avoid races. - tpm_chip_register(): tpm_dev_add_device() must be done as the last step before exposing device to the user space in order to avoid races. In addition clarified description in tpm_chip_register(). Signed-off-by: Jarkko Sakkinen --- drivers/char/tpm/tpm-chip.c | 34 ++++++++++++++-------------------- 1 file changed, 14 insertions(+), 20 deletions(-) diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c index 1d278cc..e096e9c 100644 --- a/drivers/char/tpm/tpm-chip.c +++ b/drivers/char/tpm/tpm-chip.c @@ -140,24 +140,24 @@ static int tpm_dev_add_device(struct tpm_chip *chip) { int rc; - rc = device_add(&chip->dev); + rc = cdev_add(&chip->cdev, chip->dev.devt, 1); if (rc) { dev_err(&chip->dev, - "unable to device_register() %s, major %d, minor %d, err=%d\n", + "unable to cdev_add() %s, major %d, minor %d, err=%d\n", chip->devname, MAJOR(chip->dev.devt), MINOR(chip->dev.devt), rc); + device_unregister(&chip->dev); return rc; } - rc = cdev_add(&chip->cdev, chip->dev.devt, 1); + rc = device_add(&chip->dev); if (rc) { dev_err(&chip->dev, - "unable to cdev_add() %s, major %d, minor %d, err=%d\n", + "unable to device_register() %s, major %d, minor %d, err=%d\n", chip->devname, MAJOR(chip->dev.devt), MINOR(chip->dev.devt), rc); - device_unregister(&chip->dev); return rc; } @@ -174,27 +174,17 @@ static void tpm_dev_del_device(struct tpm_chip *chip) * tpm_chip_register() - create a character device for the TPM chip * @chip: TPM chip to use. * - * Creates a character device for the TPM chip and adds sysfs interfaces for - * the device, PPI and TCPA. As the last step this function adds the - * chip to the list of TPM chips available for use. + * Creates a character device for the TPM chip and adds sysfs attributes for + * the device. As the last step this function adds the chip to the list of TPM + * chips available for in-kernel use. * - * NOTE: This function should be only called after the chip initialization - * is complete. - * - * Called from tpm_.c probe function only for devices - * the driver has determined it should claim. Prior to calling - * this function the specific probe function has called pci_enable_device - * upon errant exit from this function specific probe function should call - * pci_disable_device + * This function should be only called after the chip initialization is + * complete. */ int tpm_chip_register(struct tpm_chip *chip) { int rc; - rc = tpm_dev_add_device(chip); - if (rc) - return rc; - /* Populate sysfs for TPM1 devices. */ if (!(chip->flags & TPM_CHIP_FLAG_TPM2)) { rc = tpm_sysfs_add_device(chip); @@ -208,6 +198,10 @@ int tpm_chip_register(struct tpm_chip *chip) chip->bios_dir = tpm_bios_log_setup(chip->devname); } + rc = tpm_dev_add_device(chip); + if (rc) + return rc; + /* Make the chip available. */ spin_lock(&driver_lock); list_add_rcu(&chip->list, &tpm_chip_list); -- 2.1.4