From patchwork Wed Feb 14 14:43:00 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Lars-Peter Clausen X-Patchwork-Id: 10219157 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 61F8E601D7 for ; Wed, 14 Feb 2018 14:44:21 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 54491285F0 for ; Wed, 14 Feb 2018 14:44:21 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 492D928ED0; Wed, 14 Feb 2018 14:44:21 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 49DA5285F0 for ; Wed, 14 Feb 2018 14:43:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030786AbeBNOnO (ORCPT ); Wed, 14 Feb 2018 09:43:14 -0500 Received: from www381.your-server.de ([78.46.137.84]:43976 "EHLO www381.your-server.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1030772AbeBNOnN (ORCPT ); Wed, 14 Feb 2018 09:43:13 -0500 Received: from [88.198.220.132] (helo=sslproxy03.your-server.de) by www381.your-server.de with esmtpsa (TLSv1.2:DHE-RSA-AES256-GCM-SHA384:256) (Exim 4.85_2) (envelope-from ) id 1elyH6-0001fT-Rd; Wed, 14 Feb 2018 15:43:08 +0100 Received: from [78.47.220.141] (helo=lars-laptop.ad.analog.com) by sslproxy03.your-server.de with esmtpsa (TLSv1.2:DHE-RSA-AES128-GCM-SHA256:128) (Exim 4.84_2) (envelope-from ) id 1elyH6-00072u-3N; Wed, 14 Feb 2018 15:43:08 +0100 From: Lars-Peter Clausen To: Jonathan Cameron Cc: Hartmut Knaack , Peter Meerwald-Stadler , linux-iio@vger.kernel.org, Lars-Peter Clausen Subject: [PATCH] iio: adis_lib: Initialize trigger before requesting interrupt Date: Wed, 14 Feb 2018 15:43:00 +0100 Message-Id: <20180214144300.27550-1-lars@metafoo.de> X-Mailer: git-send-email 2.11.0 X-Authenticated-Sender: lars@metafoo.de X-Virus-Scanned: Clear (ClamAV 0.99.3/24314/Wed Feb 14 10:21:29 2018) Sender: linux-iio-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-iio@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP The adis_probe_trigger() creates a new IIO trigger and requests an interrupt associated with the trigger. The interrupt uses the generic iio_trigger_generic_data_rdy_poll() function as its interrupt handler. Currently the driver initializes some fields of the trigger structure after the interrupt has been requested. But an interrupt can fire as soon as it has been requested. This opens up a race condition. iio_trigger_generic_data_rdy_poll() will access the trigger data structure and dereference the ops field. If the ops field is not yet initialized this will result in a NULL pointer deref. It is not expected that the device generates an interrupt at this point, so typically this issue did not surface unless e.g. due to a hardware misconfiguration (wrong interrupt number, wrong polarity, etc.). But some newer devices from the ADIS family start to generate periodic interrupts in their power-on reset configuration and unfortunately the interrupt can not be masked in the device. This makes the race condition much more visible and the following crash has been observed occasionally when booting a system using the ADIS16460. Unable to handle kernel NULL pointer dereference at virtual address 00000008 pgd = c0004000 [00000008] *pgd=00000000 Internal error: Oops: 5 [#1] PREEMPT SMP ARM Modules linked in: CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.9.0-04126-gf9739f0-dirty #257 Hardware name: Xilinx Zynq Platform task: ef04f640 task.stack: ef050000 PC is at iio_trigger_notify_done+0x30/0x68 LR is at iio_trigger_generic_data_rdy_poll+0x18/0x20 pc : [] lr : [] psr: 60000193 sp : ef051bb8 ip : 00000000 fp : ef106400 r10: c081d80a r9 : ef3bfa00 r8 : 00000087 r7 : ef051bec r6 : 00000000 r5 : ef3bfa00 r4 : ee92ab00 r3 : 00000000 r2 : 00000000 r1 : 00000000 r0 : ee97e400 Flags: nZCv IRQs off FIQs on Mode SVC_32 ISA ARM Segment none Control: 18c5387d Table: 0000404a DAC: 00000051 Process swapper/0 (pid: 1, stack limit = 0xef050210) [] (iio_trigger_notify_done) from [] (__handle_irq_event_percpu+0x88/0x118) [] (__handle_irq_event_percpu) from [] (handle_irq_event_percpu+0x1c/0x58) [] (handle_irq_event_percpu) from [] (handle_irq_event+0x38/0x5c) [] (handle_irq_event) from [] (handle_level_irq+0xa4/0x130) [] (handle_level_irq) from [] (generic_handle_irq+0x24/0x34) [] (generic_handle_irq) from [] (zynq_gpio_irqhandler+0xb8/0x13c) [] (zynq_gpio_irqhandler) from [] (generic_handle_irq+0x24/0x34) [] (generic_handle_irq) from [] (__handle_domain_irq+0x5c/0xb4) [] (__handle_domain_irq) from [] (gic_handle_irq+0x48/0x8c) [] (gic_handle_irq) from [] (__irq_svc+0x6c/0xa8) To fix this make sure that the trigger is fully initialized before requesting the interrupt. Fixes: ccd2b52f4ac6 ("staging:iio: Add common ADIS library") Reported-by: Robin Getz Signed-off-by: Lars-Peter Clausen --- drivers/iio/imu/adis_trigger.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/drivers/iio/imu/adis_trigger.c b/drivers/iio/imu/adis_trigger.c index 0dd5a381be64..457372f36791 100644 --- a/drivers/iio/imu/adis_trigger.c +++ b/drivers/iio/imu/adis_trigger.c @@ -46,6 +46,10 @@ int adis_probe_trigger(struct adis *adis, struct iio_dev *indio_dev) if (adis->trig == NULL) return -ENOMEM; + adis->trig->dev.parent = &adis->spi->dev; + adis->trig->ops = &adis_trigger_ops; + iio_trigger_set_drvdata(adis->trig, adis); + ret = request_irq(adis->spi->irq, &iio_trigger_generic_data_rdy_poll, IRQF_TRIGGER_RISING, @@ -54,9 +58,6 @@ int adis_probe_trigger(struct adis *adis, struct iio_dev *indio_dev) if (ret) goto error_free_trig; - adis->trig->dev.parent = &adis->spi->dev; - adis->trig->ops = &adis_trigger_ops; - iio_trigger_set_drvdata(adis->trig, adis); ret = iio_trigger_register(adis->trig); indio_dev->trig = iio_trigger_get(adis->trig);