From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752714AbdKHPXq (ORCPT ); Wed, 8 Nov 2017 10:23:46 -0500 Received: from mail-yw0-f196.google.com ([209.85.161.196]:49915 "EHLO mail-yw0-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751304AbdKHPXn (ORCPT ); Wed, 8 Nov 2017 10:23:43 -0500 X-Google-Smtp-Source: ABhQp+TvL8NBCEXNEW7x0X0yBls0k0HYcakvTR9zsBeAJNlo7sIa+z4/stDEqW80dDD1QhXRH5gWLg== From: William Breathitt Gray To: gregkh@linuxfoundation.org Cc: fengguang.wu@intel.com, torvalds@linux-foundation.org, linux-kernel@vger.kernel.org, William Breathitt Gray Subject: [PATCH] isa: Prevent NULL dereference in isa_bus driver callbacks Date: Wed, 8 Nov 2017 10:23:11 -0500 Message-Id: <20171108152311.14469-1-vilhelm.gray@gmail.com> X-Mailer: git-send-email 2.15.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The isa_driver structure for an isa_bus device is stored in the device platform_data member of the respective device structure. This platform_data member may be reset to NULL if isa_driver match callback for the device fails, indicating a device unsupported by the ISA driver. This patch fixes a possible NULL pointer dereference if one of the isa_driver callbacks to attempted for an unsupported device. This error should not occur in practice since ISA devices are typically manually configured and loaded by the users, but we may as well prevent this error from popping up for the 0day testers. Fixes: a5117ba7da37 ("[PATCH] Driver model: add ISA bus") Signed-off-by: William Breathitt Gray --- drivers/base/isa.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/drivers/base/isa.c b/drivers/base/isa.c index cd6ccdcf9df0..372d10af2600 100644 --- a/drivers/base/isa.c +++ b/drivers/base/isa.c @@ -39,7 +39,7 @@ static int isa_bus_probe(struct device *dev) { struct isa_driver *isa_driver = dev->platform_data; - if (isa_driver->probe) + if (isa_driver && isa_driver->probe) return isa_driver->probe(dev, to_isa_dev(dev)->id); return 0; @@ -49,7 +49,7 @@ static int isa_bus_remove(struct device *dev) { struct isa_driver *isa_driver = dev->platform_data; - if (isa_driver->remove) + if (isa_driver && isa_driver->remove) return isa_driver->remove(dev, to_isa_dev(dev)->id); return 0; @@ -59,7 +59,7 @@ static void isa_bus_shutdown(struct device *dev) { struct isa_driver *isa_driver = dev->platform_data; - if (isa_driver->shutdown) + if (isa_driver && isa_driver->shutdown) isa_driver->shutdown(dev, to_isa_dev(dev)->id); } @@ -67,7 +67,7 @@ static int isa_bus_suspend(struct device *dev, pm_message_t state) { struct isa_driver *isa_driver = dev->platform_data; - if (isa_driver->suspend) + if (isa_driver && isa_driver->suspend) return isa_driver->suspend(dev, to_isa_dev(dev)->id, state); return 0; @@ -77,7 +77,7 @@ static int isa_bus_resume(struct device *dev) { struct isa_driver *isa_driver = dev->platform_data; - if (isa_driver->resume) + if (isa_driver && isa_driver->resume) return isa_driver->resume(dev, to_isa_dev(dev)->id); return 0; -- 2.15.0