pci_get_slot() returns a referenced PCI device. Commit 44c10138fd4b ("PCI: Change all drivers to use pci_device->revision") replaced a configuration-space read with direct access to the cached revision field, but left that access after pci_dev_put(). The bridge may therefore be freed before its revision is read. Read the revision before dropping the reference. Fixes: 44c10138fd4b ("PCI: Change all drivers to use pci_device->revision") Signed-off-by: Hongyan Xu <getshell@seu.edu.cn> Reviewed-by: Niklas Cassel <cassel@kernel.org> Signed-off-by: Damien Le Moal <dlemoal@kernel.org>