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PCI: Prevent sysfs disable of device while driver is attached

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[ Upstream commit 6f5cdfa802733dcb561bf664cc89d203f2fd958f ]

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>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Christoph Hellwig 2018-05-18 18:56:24 +02:00 committed by Greg Kroah-Hartman
parent d93663a787
commit 2040b0d8c9
1 changed files with 9 additions and 6 deletions
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15
drivers/pci/pci-sysfs.c
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@ -305,13 +305,16 @@ static ssize_t enable_store(struct device *dev, struct device_attribute *attr,
if (!capable(CAP_SYS_ADMIN)) if (!capable(CAP_SYS_ADMIN))
return -EPERM; return -EPERM;
if (!val) { device_lock(dev);
if (pci_is_enabled(pdev)) if (dev->driver)
pci_disable_device(pdev); result = -EBUSY;
else else if (val)
result = -EIO;
} else
result = pci_enable_device(pdev); 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; return result < 0 ? result : count;
} }