From 6f5cdfa802733dcb561bf664cc89d203f2fd958f Mon Sep 17 00:00:00 2001
From: Christoph Hellwig <hch@lst.de>
Date: Fri, 18 May 2018 18:56:24 +0200
Subject: [PATCH] PCI: Prevent sysfs disable of device while driver is attached
Git-commit: 6f5cdfa802733dcb561bf664cc89d203f2fd958f
Patch-mainline: v4.18-rc1
References: bsc#1051510
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 <hch@lst.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Acked-by: Keith Busch <keith.busch@intel.com>
Acked-by: Takashi Iwai <tiwai@suse.de>
---
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;
}
--
2.18.0