[PATCH 6.12 049/265] PCI: Use resource_set_range() that correctly sets ->end

Greg Kroah-Hartman
2026-03-12T20:15:33Z

From: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>

[ Upstream commit 11721c45a8266a9d0c9684153d20e37159465f96 ]

__pci_read_base() sets resource start and end addresses when resource
is larger than 4G but pci_bus_addr_t or resource_size_t are not capable
of representing 64-bit PCI addresses. This creates a problematic
resource that has non-zero flags but the start and end addresses do not
yield to resource size of 0 but 1.

Replace custom resource addresses setup with resource_set_range()
that correctly sets end address as -1 which results in resource_size()
returning 0.

For consistency, also use resource_set_range() in the other branch that
does size based resource setup.

Fixes: 23b13bc76f35 ("PCI: Fail safely if we can't handle BARs larger than 4GB")
Link: https://lore.kernel.org/all/20251207215359.28895-1-ansuelsmth@gmail.com/T/#m990492684913c5a158ff0e5fc90697d8ad95351b
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@intel.com>
Cc: stable@vger.kernel.org
Cc: Christian Marangi <ansuelsmth@gmail.com>
Link: https://patch.msgid.link/20251208145654.5294-1-ilpo.jarvinen@linux.intel.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/pci/probe.c | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 9e419f14738a2..9e71eb4d1010e 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -263,8 +263,7 @@ int __pci_read_base(struct pci_dev *dev, enum pci_bar_type type,
if ((sizeof(pci_bus_addr_t) < 8 || sizeof(resource_size_t) < 8)
&& sz64 > 0x100000000ULL) {
res->flags |= IORESOURCE_UNSET | IORESOURCE_DISABLED;
- res->start = 0;
- res->end = 0;
+ resource_set_range(res, 0, 0);
pci_err(dev, "%s: can't handle BAR larger than 4GB (size %#010llx)\n",
res_name, (unsigned long long)sz64);
goto out;
@@ -273,8 +272,7 @@ int __pci_read_base(struct pci_dev *dev, enum pci_bar_type type,
if ((sizeof(pci_bus_addr_t) < 8) && l) {
/* Above 32-bit boundary; try to reallocate */
res->flags |= IORESOURCE_UNSET;
- res->start = 0;
- res->end = sz64 - 1;
+ resource_set_range(res, 0, sz64);
pci_info(dev, "%s: can't handle BAR above 4GB (bus address %#010llx)\n",
res_name, (unsigned long long)l64);
goto out;
--
2.51.0