commit ca76a3a8052b71c0334d5c094859cfa340c290a8 upstream. cxl_pci_map_regblock() may return an ERR_PTR(), but cxl_pci_setup_regs() is only prepared for NULL as the error case. Pick the minimal fix for -stable backport purposes and just have cxl_pci_map_regblock() return NULL for errors. Fixes: f8a7e8c29be8 ("cxl/pci: Reserve all device regions at once") Cc: <stable@vger.kernel.org> Reviewed-by: Ira Weiny <ira.weiny@intel.com> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Link: https://lore.kernel.org/r/163433325724.834522.17809774578178224149.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>