4.9-stable review patch. If anyone has any objections, please let me know.
------------------ From: Christoph Hellwig <[email protected]> [ 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 <[email protected]> Signed-off-by: Bjorn Helgaas <[email protected]> Reviewed-by: Johannes Thumshirn <[email protected]> Acked-by: Keith Busch <[email protected]> Signed-off-by: Sasha Levin <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- 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; }
