4.4-stable review patch. If anyone has any objections, please let me know.
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From: Christoph Hellwig hch@lst.de
[ 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 --- drivers/pci/pci-sysfs.c | 15 +++++++++------ 1 file changed, 9 insertions(+), 6 deletions(-)
--- a/drivers/pci/pci-sysfs.c +++ b/drivers/pci/pci-sysfs.c @@ -180,13 +180,16 @@ static ssize_t enable_store(struct devic 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; }