Re: [Linux-kernel-mentees] [PATCH 8/14 v3] PCI/ACPI: Check the return value of pcie_capability_read_*()
From: "Rafael J. Wysocki" <rafael@kernel.org>
Date: 2020-07-14 13:27:53
Also in:
linux-acpi, linux-pci, lkml
On Mon, Jul 13, 2020 at 6:55 PM Saheed O. Bolarinwa [off-list ref] wrote:
From: Bolarinwa Olayemi Saheed <redacted> On failure pcie_capability_read_dword() sets it's last parameter, val to 0. However, with Patch 14/14, it is possible that val is set to ~0 on failure. This would introduce a bug because (x & x) == (~0 & x). This bug can be avoided if the return value of pcie_capability_read_word is checked to confirm success. Check the return value of pcie_capability_read_word() to ensure success. Suggested-by: Bjorn Helgaas <redacted> Signed-off-by: Bolarinwa Olayemi Saheed <redacted>
Acked-by: Rafael J. Wysocki <redacted>
quoted hunk ↗ jump to hunk
--- drivers/pci/pci-acpi.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-)diff --git a/drivers/pci/pci-acpi.c b/drivers/pci/pci-acpi.c index 7224b1e5f2a8..39eb816bc3b8 100644 --- a/drivers/pci/pci-acpi.c +++ b/drivers/pci/pci-acpi.c@@ -248,12 +248,13 @@ static bool pcie_root_rcb_set(struct pci_dev *dev) { struct pci_dev *rp = pcie_find_root_port(dev); u16 lnkctl; + int ret; if (!rp) return false; - pcie_capability_read_word(rp, PCI_EXP_LNKCTL, &lnkctl); - if (lnkctl & PCI_EXP_LNKCTL_RCB) + ret = pcie_capability_read_word(rp, PCI_EXP_LNKCTL, &lnkctl); + if (!ret && (lnkctl & PCI_EXP_LNKCTL_RCB)) return true; return false;@@ -792,12 +793,13 @@ bool pciehp_is_native(struct pci_dev *bridge) { const struct pci_host_bridge *host; u32 slot_cap; + int ret; if (!IS_ENABLED(CONFIG_HOTPLUG_PCI_PCIE)) return false; - pcie_capability_read_dword(bridge, PCI_EXP_SLTCAP, &slot_cap); - if (!(slot_cap & PCI_EXP_SLTCAP_HPC)) + ret = pcie_capability_read_dword(bridge, PCI_EXP_SLTCAP, &slot_cap); + if (ret || !(slot_cap & PCI_EXP_SLTCAP_HPC)) return false; if (pcie_ports_native) --2.18.2
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