From: Yadi.hu Date: Sun, 18 Sep 2016 10:52:31 +0000 (+0800) Subject: i2c-eg20t: fix race between i2c init and interrupt enable X-Git-Tag: v3.2.84~18 X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?p=pandora-kernel.git;a=commitdiff_plain;h=25a0d70d6162a76eebfbff33acd5746d99c32c4e;ds=inline i2c-eg20t: fix race between i2c init and interrupt enable commit 371a015344b6e270e7e3632107d9554ec6d27a6b upstream. the eg20t driver call request_irq() function before the pch_base_address, base address of i2c controller's register, is assigned an effective value. there is one possible scenario that an interrupt which isn't inside eg20t arrives immediately after request_irq() is executed when i2c controller shares an interrupt number with others. since the interrupt handler pch_i2c_handler() has already active as shared action, it will be called and read its own register to determine if this interrupt is from itself. At that moment, since base address of i2c registers is not remapped in kernel space yet,so the INT handler will access an illegal address and then a error occurs. Signed-off-by: Yadi.hu Signed-off-by: Wolfram Sang Signed-off-by: Ben Hutchings --- diff --git a/drivers/i2c/busses/i2c-eg20t.c b/drivers/i2c/busses/i2c-eg20t.c index 2cda65bf2c0e..46f7bea0385c 100644 --- a/drivers/i2c/busses/i2c-eg20t.c +++ b/drivers/i2c/busses/i2c-eg20t.c @@ -893,13 +893,6 @@ 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++) { pch_adap = &adap_info->pch_data[i].pch_adapter; adap_info->pch_i2c_suspended = false; @@ -916,6 +909,17 @@ static int __devinit pch_i2c_probe(struct pci_dev *pdev, adap_info->pch_data[i].pch_base_address = base_addr + 0x100 * i; pch_adap->dev.parent = &pdev->dev; + } + + 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++) { + pch_adap = &adap_info->pch_data[i].pch_adapter; pch_i2c_init(&adap_info->pch_data[i]); ret = i2c_add_adapter(pch_adap);