From 6f5cdfa802733dcb561bf664cc89d203f2fd958f Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Fri, 18 May 2018 18:56:24 +0200 Subject: [PATCH] PCI: Prevent sysfs disable of device while driver is attached Manipulating the enable_cnt behind the back of the driver will wreak complete havoc with the kernel state, so disallow it. Signed-off-by: Christoph Hellwig Signed-off-by: Bjorn Helgaas Reviewed-by: Johannes Thumshirn Acked-by: Keith Busch --- drivers/pci/pci-sysfs.c | 15 +++++++++------ 1 file changed, 9 insertions(+), 6 deletions(-) diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c index 366d93af051d..788a200fb2dc 100644 --- a/drivers/pci/pci-sysfs.c +++ b/drivers/pci/pci-sysfs.c @@ -288,13 +288,16 @@ static ssize_t enable_store(struct device *dev, struct device_attribute *attr, if (!capable(CAP_SYS_ADMIN)) return -EPERM; - if (!val) { - if (pci_is_enabled(pdev)) - pci_disable_device(pdev); - else - result = -EIO; - } else + device_lock(dev); + if (dev->driver) + result = -EBUSY; + else if (val) result = pci_enable_device(pdev); + else if (pci_is_enabled(pdev)) + pci_disable_device(pdev); + else + result = -EIO; + device_unlock(dev); return result < 0 ? result : count; }