Linux PCI subsystem development
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From: "Ilpo Järvinen" <ilpo.jarvinen@linux.intel.com>
To: Bjorn Helgaas <bhelgaas@google.com>,
	linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org
Cc: "Ilpo Järvinen" <ilpo.jarvinen@linux.intel.com>,
	stable@vger.kernel.org,
	"Christian Marangi" <ansuelsmth@gmail.com>
Subject: [PATCH 1/1] PCI: Use resource_set_range() that correctly sets ->end
Date: Mon,  8 Dec 2025 16:56:54 +0200	[thread overview]
Message-ID: <20251208145654.5294-1-ilpo.jarvinen@linux.intel.com> (raw)

__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>
Cc: stable@vger.kernel.org
Cc: Christian Marangi <ansuelsmth@gmail.com>
---
 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 124d2d309c58..b8294a2f11f9 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -287,8 +287,7 @@ 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;
@@ -297,8 +296,7 @@ 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;

base-commit: 43dfc13ca972988e620a6edb72956981b75ab6b0
-- 
2.39.5


             reply	other threads:[~2025-12-08 14:57 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-12-08 14:56 Ilpo Järvinen [this message]
2025-12-08 15:15 ` [PATCH 1/1] PCI: Use resource_set_range() that correctly sets ->end Andy Shevchenko
2025-12-10 17:13 ` Bjorn Helgaas
2025-12-10 17:17   ` Christian Marangi
2025-12-10 21:30 ` Bjorn Helgaas

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