From a231707a91f323af1e5d9f1722055ec2fc1c7775 Mon Sep 17 00:00:00 2001 From: Aleksandr Mishin Date: Sun, 5 May 2024 09:15:17 +0300 Subject: [PATCH] PCI: keystone: Fix NULL pointer dereference in case of DT error in ks_pcie_setup_rc_app_regs() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit If IORESOURCE_MEM is not provided in Device Tree due to any error, resource_list_first_type() will return NULL and pci_parse_request_of_pci_ranges() will just emit a warning. This will cause a NULL pointer dereference. Fix this bug by adding NULL return check. Found by Linux Verification Center (linuxtesting.org) with SVACE. Fixes: 0f71c60ffd26 ("PCI: dwc: Remove storing of PCI resources") Link: https://lore.kernel.org/linux-pci/20240505061517.11527-1-amishin@t-argos.ru Suggested-by: Bjorn Helgaas Suggested-by: Manivannan Sadhasivam Signed-off-by: Aleksandr Mishin Signed-off-by: Krzysztof Wilczyński Signed-off-by: Bjorn Helgaas Reviewed-by: Manivannan Sadhasivam --- drivers/pci/controller/dwc/pci-keystone.c | 20 +++++++++++++++----- 1 file changed, 15 insertions(+), 5 deletions(-) diff --git a/drivers/pci/controller/dwc/pci-keystone.c b/drivers/pci/controller/dwc/pci-keystone.c index 57135eee2d7d..cd0e0022f91d 100644 --- a/drivers/pci/controller/dwc/pci-keystone.c +++ b/drivers/pci/controller/dwc/pci-keystone.c @@ -400,17 +400,22 @@ static const struct irq_domain_ops ks_pcie_intx_irq_domain_ops = { .xlate = irq_domain_xlate_onetwocell, }; -static void ks_pcie_setup_rc_app_regs(struct keystone_pcie *ks_pcie) +static int ks_pcie_setup_rc_app_regs(struct keystone_pcie *ks_pcie) { u32 val; u32 num_viewport = ks_pcie->num_viewport; struct dw_pcie *pci = ks_pcie->pci; struct dw_pcie_rp *pp = &pci->pp; - u64 start, end; + struct resource_entry *entry; struct resource *mem; + u64 start, end; int i; - mem = resource_list_first_type(&pp->bridge->windows, IORESOURCE_MEM)->res; + entry = resource_list_first_type(&pp->bridge->windows, IORESOURCE_MEM); + if (!entry) + return -ENODEV; + + mem = entry->res; start = mem->start; end = mem->end; @@ -421,7 +426,7 @@ static void ks_pcie_setup_rc_app_regs(struct keystone_pcie *ks_pcie) ks_pcie_clear_dbi_mode(ks_pcie); if (ks_pcie->is_am6) - return; + return 0; val = ilog2(OB_WIN_SIZE); ks_pcie_app_writel(ks_pcie, OB_SIZE, val); @@ -438,6 +443,8 @@ static void ks_pcie_setup_rc_app_regs(struct keystone_pcie *ks_pcie) val = ks_pcie_app_readl(ks_pcie, CMD_STATUS); val |= OB_XLAT_EN_VAL; ks_pcie_app_writel(ks_pcie, CMD_STATUS, val); + + return 0; } static void __iomem *ks_pcie_other_map_bus(struct pci_bus *bus, @@ -798,7 +805,10 @@ static int __init ks_pcie_host_init(struct dw_pcie_rp *pp) return ret; ks_pcie_stop_link(pci); - ks_pcie_setup_rc_app_regs(ks_pcie); + ret = ks_pcie_setup_rc_app_regs(ks_pcie); + if (ret) + return ret; + writew(PCI_IO_RANGE_TYPE_32 | (PCI_IO_RANGE_TYPE_32 << 8), pci->dbi_base + PCI_IO_BASE);