From mboxrd@z Thu Jan 1 00:00:00 1970 From: Yadi Hu Subject: [PATCH] i2c-eg20t: fix race between i2c init and interrupt enable Date: Tue, 23 Aug 2016 17:07:19 +0800 Message-ID: <1471943239-21420-1-git-send-email-yadi.hu@windriver.com> Mime-Version: 1.0 Content-Type: text/plain Return-path: Received: from mail.windriver.com ([147.11.1.11]:44314 "EHLO mail.windriver.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753834AbcHWJJL (ORCPT ); Tue, 23 Aug 2016 05:09:11 -0400 Sender: linux-i2c-owner@vger.kernel.org List-Id: linux-i2c@vger.kernel.org To: yadi.hu@windriver.com, jdelvare@suse.com, khali@linux-fr.org, wsa@the-dreams.de Cc: linux-i2c@vger.kernel.org From: Hu Yadi The driver executes request_irq() function before the base address of i2c registers is remapped in kernel space. If i2c controller shares an interrupt line with other devices,it is possible that an interrupt arrives immediately after request_irq() is called. Since the interrupt handler pch_i2c_handler() is active, it will read its own register to determine if this interrupt was from its device. At this moment, base address of i2c registers is not remapped in kernel space yet,so the INT handler access a unknown address and a error occurs. Signed-off-by: Hu Yadi --- drivers/i2c/busses/i2c-eg20t.c | 25 ++++++++++++++----------- 1 files changed, 14 insertions(+), 11 deletions(-) diff --git a/drivers/i2c/busses/i2c-eg20t.c b/drivers/i2c/busses/i2c-eg20t.c index c811289..7a51ddc 100644 --- a/drivers/i2c/busses/i2c-eg20t.c +++ b/drivers/i2c/busses/i2c-eg20t.c @@ -893,15 +893,8 @@ static int __devinit pch_i2c_probe(struct pci_dev *pdev, /* Set the number of I2C channel instance */ adap_info->ch_num = id->driver_data; - - ret = request_irq(pdev->irq, pch_i2c_handler, IRQF_SHARED, - KBUILD_MODNAME, adap_info); - if (ret) { - pch_pci_err(pdev, "request_irq FAILED\n"); - goto err_request_irq; - } - - for (i = 0; i < adap_info->ch_num; i++) { + + for (i = 0; i < adap_info->ch_num; i++) { pch_adap = &adap_info->pch_data[i].pch_adapter; adap_info->pch_i2c_suspended = false; @@ -928,15 +921,25 @@ static int __devinit pch_i2c_probe(struct pci_dev *pdev, } } + + + ret = request_irq(pdev->irq, pch_i2c_handler, IRQF_SHARED, + KBUILD_MODNAME, adap_info); + if (ret) { + pch_pci_err(pdev, "request_irq FAILED\n"); + goto err_request_irq; + } + pci_set_drvdata(pdev, adap_info); pch_pci_dbg(pdev, "returns %d.\n", ret); return 0; + +err_request_irq: + free_irq(pdev->irq, adap_info); err_add_adapter: for (j = 0; j < i; j++) i2c_del_adapter(&adap_info->pch_data[j].pch_adapter); - free_irq(pdev->irq, adap_info); -err_request_irq: pci_iounmap(pdev, base_addr); err_pci_iomap: pci_release_regions(pdev); -- 1.7.5.4