[PATCH AUTOSEL 5.10 19/38] PCI: al: Check IORESOURCE_BUS existence during probe

Sasha Levin
2024-08-01T00:38:06Z

From: Aleksandr Mishin <amishin@t-argos.ru>

[ Upstream commit a9927c2cac6e9831361e43a14d91277818154e6a ]

If IORESOURCE_BUS is not provided in Device Tree it will be fabricated in
of_pci_parse_bus_range(), so NULL pointer dereference should not happen
here.

But that's hard to verify, so check for NULL anyway.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Link: https://lore.kernel.org/linux-pci/20240503125705.46055-1-amishin@t-argos.ru
Suggested-by: Bjorn Helgaas <helgaas@kernel.org>
Signed-off-by: Aleksandr Mishin <amishin@t-argos.ru>
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
[bhelgaas: commit log]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/pci/controller/dwc/pcie-al.c | 16 +++++++++++++---
1 file changed, 13 insertions(+), 3 deletions(-)

diff --git a/drivers/pci/controller/dwc/pcie-al.c b/drivers/pci/controller/dwc/pcie-al.c
index f973fbca90cf7..ac772fb11aa73 100644
--- a/drivers/pci/controller/dwc/pcie-al.c
+++ b/drivers/pci/controller/dwc/pcie-al.c
@@ -250,18 +250,24 @@ static struct pci_ops al_child_pci_ops = {
.write = pci_generic_config_write,
};

-static void al_pcie_config_prepare(struct al_pcie *pcie)
+static int al_pcie_config_prepare(struct al_pcie *pcie)
{
struct al_pcie_target_bus_cfg *target_bus_cfg;
struct pcie_port *pp = &pcie->pci->pp;
unsigned int ecam_bus_mask;
+ struct resource_entry *ft;
u32 cfg_control_offset;
+ struct resource *bus;
u8 subordinate_bus;
u8 secondary_bus;
u32 cfg_control;
u32 reg;
- struct resource *bus = resource_list_first_type(&pp->bridge->windows, IORESOURCE_BUS)->res;

+ ft = resource_list_first_type(&pp->bridge->windows, IORESOURCE_BUS);
+ if (!ft)
+ return -ENODEV;
+
+ bus = ft->res;
target_bus_cfg = &pcie->target_bus_cfg;

ecam_bus_mask = (pcie->ecam_size >> 20) - 1;
@@ -295,6 +301,8 @@ static void al_pcie_config_prepare(struct al_pcie *pcie)
FIELD_PREP(CFG_CONTROL_SEC_BUS_MASK, secondary_bus);

al_pcie_controller_writel(pcie, cfg_control_offset, reg);
+
+ return 0;
}

static int al_pcie_host_init(struct pcie_port *pp)
@@ -313,7 +321,9 @@ static int al_pcie_host_init(struct pcie_port *pp)
if (rc)
return rc;

- al_pcie_config_prepare(pcie);
+ rc = al_pcie_config_prepare(pcie);
+ if (rc)
+ return rc;

return 0;
}
--
2.43.0